Journal articles: 'Non-ferromagnetic thin film'

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Shlyakhtich, Maria A., and Pavel V. Prudnikov. "Non-equilibrium critical behavior of Heisenberg thin films." EPJ Web of Conferences 185 (2018): 11005. http://dx.doi.org/10.1051/epjconf/201818511005.

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In this work we study the non-equilibrium properties of Heisenberg ferromagnetic films using Monte Carlo simulations by short-time dynamic method. By exploring the short-time scaling dynamics, we have found thickness dependency of critical exponents z, θ′ and β/v for ferromagnetic thin film. For calculating the critical exponents of ferromagnetic films we considered systems with linear size L = 128 and layers number N = 2; 4; 6; 10. Starting from initial configurations, the system was updated with Metropolis algorithm at the critical temperatures

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Zelent, M., M. Mailyan, V. Vashistha, P. Gruszecki, O. Y. Gorobets, Y. I. Gorobets, and M. Krawczyk. "Spin wave collimation using a flat metasurface." Nanoscale 11, no. 19 (2019): 9743–48. http://dx.doi.org/10.1039/c8nr10484k.

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In this paper, we show that the phase shift of spin waves propagating in the plane of the film can be controlled by a metasurface formed by an ultra-narrow non-magnetic spacer separating edges of the two thin ferromagnetic films. We used this approach to demonstrate numerically the metalens for spin waves.

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Murayama, Y., and K. Koike. "Non-RKKY mechanism of polarization in Au thin film deposited onto ferromagnetic Fe." Journal of Magnetism and Magnetic Materials 140-144 (February 1995): 659–60. http://dx.doi.org/10.1016/0304-8853(94)01038-2.

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Lee, Sang A., Jong Mok Ok, Jegon Lee, Jae‐Yeol Hwang, Sangmoon Yoon, Se‐Jeong Park, Sehwan Song, et al. "Epitaxial Stabilization of Metastable 3C BaRuO 3 Thin Film with Ferromagnetic Non‐Fermi Liquid Phase." Advanced Electronic Materials 7, no. 4 (March 12, 2021): 2001111. http://dx.doi.org/10.1002/aelm.202001111.

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Muratov, Cyrill B., and Xiaodong Yan. "Uniqueness of one-dimensional Néel wall profiles." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 472, no. 2187 (March 2016): 20150762. http://dx.doi.org/10.1098/rspa.2015.0762.

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We study the domain wall structure in thin uniaxial ferromagnetic films in the presence of an in-plane applied external field in the direction normal to the easy axis. Using the reduced one-dimensional thin-film micromagnetic model, we analyse the critical points of the obtained non-local variational problem. We prove that the minimizer of the one-dimensional energy functional in the form of the Néel wall is the unique (up to translations) critical point of the energy among all monotone profiles with the same limiting behaviour at infinity. Thus, we establish uniqueness of the one-dimensional monotone Néel wall profile in the considered setting. We also obtain some uniform estimates for general one-dimensional domain wall profiles.

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Swindells, C., and D. Atkinson. "Interface enhanced precessional damping in spintronic multilayers: A perspective." Journal of Applied Physics 131, no. 17 (May 7, 2022): 170902. http://dx.doi.org/10.1063/5.0080267.

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In the past two decades, there have been huge developments in the understanding of damping in multilayered thin films and, more generally, in spin-transport in spintronic systems. In multilayered ferromagnetic (FM)/non-magnetic (NM) thin-film systems, observations of ferromagnetic resonant precession show a strong increase in the fundamental damping when the FM thin films are layered with heavy metals, such as Pt. These observations led to significant theoretical developments, dominated by the “spin-pumping” formalism, which describes the enhancement of damping in terms of the propagation or “pumping” of spin-current across the interface from the precessing magnetization into the heavy metal. This paper presents a perspective that introduces the key early experimental damping results in FM/NM systems and outlines the theoretical models developed to explain the enhanced damping observed in these systems. This is followed by a wider discussion of a range of experimental results in the context of the theoretical models, highlighting agreement between the theory and experiment, and more recent observations that have required further theoretical consideration, in particular, with respect to the role of the interfaces and proximity-induced magnetism in the heavy metal layer. The Perspective concludes with an outline discussion of spin-pumping in the broader context of spin-transport.

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Huang, Angus, Sheng-Hsiung Hung, and Horng-Tay Jeng. "Strain Induced Metal–Insulator Transition of Magnetic SrRuO3 Single Layer in SrRuO3/SrTiO3 Superlattice." Applied Sciences 8, no. 11 (November 3, 2018): 2151. http://dx.doi.org/10.3390/app8112151.

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Ferromagnetic phase in a two-dimensional system plays an important role not only in applications but also in studies of phase transition theory. Among numerous ferromagnetic materials, Sr Ru O 3 is famous for its half-metallicity, itinerant ferromagnetism and non-Fermi liquid metalicity. Single layer Sr Ru O 3 in Sr Ru O 3 / Sr Ti O 3 (SRO/STO) superlattice has been predicted as a two-dimensional half-metallic ferromagnetic system based on density functional theory (DFT). However, experiments show that metal–insulator transition associated with ferro–antiferromagnetism (FM–AFM) transition occurs when the thickness of SRO is less than 4 u.c. Combining DFT calculations with Monte Carlo simulations, we demonstrate in this work that the bulk ferromagnetic metallicity can be realized in single layer SRO in SRO/STO superlattice by manipulating the strain effect to trigger the metal–insulator transition, achieving two-dimensional (2D) half-metallic SRO thin film beyond the experimental observation of AFM insulator.Our results pave a new route to fulfill the ultrathin spin-polarized-2D electron gas (SP-2DEG).

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Mohanty, P., V. Ganeshan, and Chandana Rath. "Room Temperature Ferromagnetism in Ti_0.985Co_0.015O_2-δ Thin Films Grown by Pulsed Laser Deposition Technique." Materials Science Forum 760 (July 2013): 1–7. http://dx.doi.org/10.4028/www.scientific.net/msf.760.1.

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Ti0.985Co0.015O2-δ thin films are deposited at 0, 0.1, 1 and 300 mTorr oxygen partial pressures by pulsed laser deposition (PLD) technique. Glancing angle x- ray diffraction (GAXRD) and micro-Raman spectroscopy show that the phase changes from rutile to anatase with increasing oxygen partial pressure. From Rutherford backscattering spectroscopic (RBS) technique, O to (Ti+Co) atomic ratio is found to increase with increasing oxygen partial pressure. Further, the simulation of RBS data while reveals non-uniform distribution of Co throughout the film deposited at 0 and 0.1 mTorr oxygen partial pressures, at 1 and 300 mTorr oxygen partial pressure, Co distribution is found to be uniform. Magnetic measurements confirm the room temperature ferromagnetism (RTFM) in all the films independent of the phase. Magnetic force microscopy (MFM) further supports the ferromagnetic nature of the films. We attribute the ferromagnetism in the films to be arisen from defects like oxygen vacancies rather than any contamination or Co clustering.

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Grimes, M., N. Gurung, H. Ueda, D. G. Porter, B. Pedrini, L. J. Heyderman, T. Thomson, and V. Scagnoli. "X-ray investigation of long-range antiferromagnetic ordering in FeRh." AIP Advances 12, no. 3 (March 1, 2022): 035048. http://dx.doi.org/10.1063/9.0000320.

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We demonstrate a probe of long-range antiferromagnetic (AF) order in FeRh thin films using non-resonant magnetic x-ray scattering. In particular, x-rays at energies below the Fe K-edge have been used for the observation of magnetic Bragg peaks. Due to the low efficiency of the magnetic scattering, a grazing incidence geometry was used to optimise the diffracted intensity from the thin film samples. Based on Scherrer analysis, we estimate a coherence length similar to previous reports from x-ray magnetic linear dichroism (XMLD) experiments, indicating that domain sizes are limited to 40 nm which is consistent with the grain size. The temperature dependent behaviour of the AF order shows an inverse correlation with the emergence of the ferromagnetic (FM) moment, as expected from the phase diagram.

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PADHAN, PRAHALLAD, and R. C. BUDHANI. "PERPENDICULAR-TO-PLANE MAGNETORESISTANCE IN La0.7Ca0.3MnO3/LaNiO3 SUPERLATTICES: THE EFFECTS OF INTERFACIAL DISORDER AND SPIN DIFFUSION ON CHARGE TRANSPORT." Modern Physics Letters B 17, no. 29n30 (December 30, 2003): 1517–26. http://dx.doi.org/10.1142/s021798490300658x.

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Current perpendicular-to-plane (CPP) magnetoresistance (MR) of La 0.7 Ca 0.3 MnO 3/ LaNiO 3 superlattices sandwiched between two YBa 2 Cu 3 O 7 thin film electrodes is reported. The CPP-MR in the temperature window of 20 K to 80 K is larger by a factor of 7~15 compared to current-in-plane (CIP) MR. Both CPP and CIP-magnetoresistance decrease with temperature below ~ 20 K. The MR at T<40 K is also strongly hysteretic and does not saturate even at 4 Tesla. Measurements of saturation moment and modeling of the perpendicular-to-plane resistance suggest disorder at the ferromagnetic non-magnetic layer interfaces which dominate the MR. The relative orientation of magnetization in the ferromagnetic layers seems to play only a subservient role in the creation of magnetoresistance.

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Melnikov, Grigory Yu, Vladimir N. Lepalovskij, Andrey V. Svalov, Alexander P. Safronov, and Galina V. Kurlyandskaya. "Magnetoimpedance Thin Film Sensor for Detecting of Stray Fields of Magnetic Particles in Blood Vessel." Sensors 21, no. 11 (May 22, 2021): 3621. http://dx.doi.org/10.3390/s21113621.

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Multilayered [FeNi (100 nm)/Cu (3 nm)]5/Cu (500 nm)/[Cu (3 nm)/[FeNi (100 nm)]5 structures were used as sensitive elements of the magnetoimpedance (MI) sensor prototype for model experiments of the detection of magnetic particles in blood vessel. Non-ferromagnetic cylindrical polymer rod with a small magnetic inclusion was used as a sample mimicking thrombus in a blood vessel. The polymer rod was made of epoxy resin with an inclusion of an epoxy composite containing 30% weight fraction of commercial magnetite microparticles. The position of the magnetic inclusion mimicking thrombus in the blood vessel was detected by the measurements of the stray magnetic fields of microparticles using MI element. Changes of the MI ratio in the presence of composite can be characterized by the shift and the decrease of the maximum value of the MI. We were able to detect the position of the magnetic composite sample mimicking thrombus in blood vessels. Comsol modeling was successfully used for the analysis of the obtained experimental results and the understanding of the origin the MI sensitivity in proposed configuration. We describe possible applications of studied configuration of MI detection for biomedical applications in the field of thrombus state evaluation and therapy.

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Ramli, Mitra Djamal, Freddy Haryanto, Sparisoma Viridi, and Khairurrijal. "Giant Magnetoresistance in (Ni₆₀Co₃₀Fe₁₀/Cu) Trilayer Growth by Opposed Target Magnetron Sputtering." Advanced Materials Research 535-537 (June 2012): 1319–22. http://dx.doi.org/10.4028/www.scientific.net/amr.535-537.1319.

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The giant magnetoresistance thin film of (Ni60Co30Fe10/Cu) trilayer were grown onto Si (100) substrate by dc-opposed target magnetron sputtering (dc-OTMS) technique. The growth parameters are: temperature of 100 0C, applied voltage of 600 volt, flow rate of Ar gas of 100 sccm, and growth pressure of 5.2 x10-1 Torr. The effects of Cu layer thickness and NiCoFe layer thickness on giant magnetoresistance (GMR) property of (Ni60Co30Fe10/Cu) trilayer were studied. We have found that the giant magnetoresistance (GMR) ratio of the sample was varied depend on the non-magnetic (Cu) layer thickness. The variation of Cu layer thickness presents an oscillatory behavior of GMR ratio. This oscillation reflects the exchange coupling oscillations between ferromagnetic and antiferromagnetic states, which are caused by an oscillation in the sign of the interlayer exchange coupling between ferromagnetic layers. The GMR ratio is change with increasing of NiCoFe layer thickness and presents GMR ratio of 70.0 % at tNiCoFe = 62.5 nm.

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J. Unguris, R. J. Celotta, and D. T. Pierce. "Scanning Electron Microscopy With Polarization Analysis (Sempa) Investigations Of Multilayer Magnetism." Microscopy and Microanalysis 5, S2 (August 1999): 40–41. http://dx.doi.org/10.1017/s1431927600013520.

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Mulitlayers consisting of various combinations of 1-10 nm thick ferromagnetic, antiferromagnetic and nonmagnetic films have numerous applications in magnetic recording, non-volatile data storage, and sensor technologies. One key aspect to understanding how these devices work is being able to image their magnetic structure. SEMPA is well suited for this job, because of its surface sensitivity and compatibility with thin film growth and surface analysis techniques. This talk will review the SEMPA technique and describe thep use of SEMPA in two examples; one in which the magnetization is imaged while growing a multilayer, and another which examines the magnetization while depth profiling a multilayer by ion milling.A SEMPA investigation of the magnetic exchange coupling in an Fe/Cr/Fe sandwich is shown in Figs. 1 and 2. A wedge shaped Cr interlayer was grown as shown in Fig. 1 in order to measure the Cr thickness dependence of the exchange coupling.

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Demirer, Figen Ece, Chris van den Bomen, Reinoud Lavrijsen, Jos J. G. M. van der Tol, and Bert Koopmans. "Design and Modelling of a Novel Integrated Photonic Device for Nano-Scale Magnetic Memory Reading." Applied Sciences 10, no. 22 (November 21, 2020): 8267. http://dx.doi.org/10.3390/app10228267.

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Design and simulations of an integrated photonic device that can optically detect the magnetization direction of its ultra-thin (∼12 nm) metal cladding, thus ‘reading’ the stored magnetic memory, are presented. The device is an unbalanced Mach Zehnder Interferometer (MZI) based on InP Membrane on Silicon (IMOS) platform. The MZI consists of a ferromagnetic thin-film cladding and a delay line in one branch, and a polarization converter in the other. It quantitatively measures the non-reciprocal phase shift caused by the Magneto-Optic Kerr Effect in the guided mode which depends on the memory bit’s magnetization direction. The current design is an analytical tool for research exploration of all-optical magnetic memory reading. It has been shown that the device is able to read a nanoscale memory bit (400 × 50 × 12 nm) by using a Kerr rotation as small as 0.2∘, in the presence of a noise ∼10 dB in terms of signal-to-noise ratio. The device is shown to tolerate performance reductions that can arise during the fabrication.

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Mantion, S., and N. Biziere. "Influence of Ga⁺ milling on the spin waves modes in a Co₂MnSi Heusler magnonic crystal." Journal of Applied Physics 131, no. 11 (March 21, 2022): 113905. http://dx.doi.org/10.1063/5.0085623.

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Ferromagnetic resonance experiment was performed to study the magnonic modes of an antidot lattice nanopatterned in a sputtered Co2MnSi Heusler alloy thin film. The magnonic crystal was prepared with a Ga+ focused ion beam, and micromagnetic simulations were used to explain qualitatively and quantitatively the complex experimental spin waves spectrum. We demonstrate the necessity to consider the geometrical imperfections and the modification of the Co2MnSi magnetic parameters induced by the nanofabrication process to describe the evolution of the frequencies and spatial profiles of the principal experimental spin waves modes in the 0–300 mT magnetic field range. In particular, our model suggests that Ga+ milling induces a drastic decrease (between 80% and 90%) in the bulk Co2MnSi magnetic parameters. In addition, simulations reveal the presence of a diversity of localized and extended spin waves modes whose spatial profiles are closely related to the evolution of the magnetic state at equilibrium from a very non-collinear configuration up to a quasi-saturated state.

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Kapran, Olena M., Roman Morari, Taras Golod, Evgenii A. Borodianskyi, Vladimir Boian, Andrei Prepelita, Nikolay Klenov, Anatoli S. Sidorenko, and Vladimir M. Krasnov. "In situ transport characterization of magnetic states in Nb/Co superconductor/ferromagnet heterostructures." Beilstein Journal of Nanotechnology 12 (August 17, 2021): 913–23. http://dx.doi.org/10.3762/bjnano.12.68.

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Employment of the non-trivial proximity effect in superconductor/ferromagnet (S/F) heterostructures for the creation of novel superconducting devices requires accurate control of magnetic states in complex thin-film multilayers. In this work, we study experimentally in-plane transport properties of microstructured Nb/Co multilayers. We apply various transport characterization techniques, including magnetoresistance, Hall effect, and the first-order-reversal-curves (FORC) analysis. We demonstrate how FORC can be used for detailed in situ characterization of magnetic states. It reveals that upon reduction of the external field, the magnetization in ferromagnetic layers first rotates in a coherent scissor-like manner, then switches abruptly into the antiparallel state and after that splits into the polydomain state, which gradually turns into the opposite parallel state. The polydomain state is manifested by a profound enhancement of resistance caused by a flux-flow phenomenon, triggered by domain stray fields. The scissor state represents the noncollinear magnetic state in which the unconventional odd-frequency spin-triplet order parameter should appear. The non-hysteretic nature of this state allows for reversible tuning of the magnetic orientation. Thus, we identify the range of parameters and the procedure for in situ control of devices based on S/F heterostructures.

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Panas, A. I., S. G. Chigarev, E. A. Vilkov, and O. A. Byshevski-Konopko. "Appearance of Intrinsic Magnetization in FeMn Antiferromagnetic Film under the Action of Spin-Polarized Current." Nano- i Mikrosistemnaya Tehnika 22, no. 8 (October 23, 2020): 438–46. http://dx.doi.org/10.17587/nmst.22.438-446.

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The article presents the results of research of two spin-injection sources of THz radiation using different structures of thin-film magnetic transitions (MT) with antiferromagnetic (AFM) FeMn film of nanoscale thickness and ferromagnetic (FM) Fe layer. In both variants, the possibility of intrinsic magnetization forming in the AFM film under the action of a spin-polarized current of a relatively small value formed in the FM layer is shown. The physical foundations of this effect based on the AFM sublattices beveling by a spin-polarized current due to the sd-exchange interaction of the conduction electrons spins with the spins of d electrons of the FM crystal lattice are considered. This does not require an external magnetic field. sd-exchange mechanism of excitation of intrinsic magnetization in AFM is an alternative to the spin-orbit mechanism, which has been widely considered recently. The relations for calculating the frequency and power of spin-injection radiation are given. New experimental results have been obtained that develop the concept of the AFM's intrinsic magnetization. The non-thermal nature of spin-injection radiation and the possibility of increasing the efficiency of the emitter operation due to the ordering of the MT structure by an external magnetic field are shown. The way of increasing the efficiency of spin-injection emitters by creating structures with multiple independently operating micro-emitters at frequencies close to 16 THz and with a signal power of up to a hundred microwatts has been determined. In general, it is shown that the use of the effect of excitation of intrinsic magnetization in AFM is of interest, both from the point of view of the development of theoretical ideas about the magnetic properties of AFM, and from a practical point of view for the creation of spin-injection lasers (tasers).

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Dede, M., K. Ürkmen, Ö. Girişen, M. Atabak, A. Oral, I. Farrer, and D. Ritchie. "Scanning Hall Probe Microscopy (SHPM) Using Quartz Crystal AFM Feedback." Journal of Nanoscience and Nanotechnology 8, no. 2 (February 1, 2008): 619–22. http://dx.doi.org/10.1166/jnn.2008.a265.

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Scanning Hall Probe Microscopy (SHPM) is a quantitative and non-invasive technique for imaging localized surface magnetic field fluctuations such as ferromagnetic domains with high spatial and magnetic field resolution of ∼50 nm and 7 mG/Hz½ at room temperature. In the SHPM technique, scanning tunneling microscope (STM) or atomic force microscope (AFM) feedback is used to keep the Hall sensor in close proximity of the sample surface. However, STM tracking SHPM requires conductive samples; therefore the insulating substrates have to be coated with a thin layer of gold. This constraint can be eliminated with the AFM feedback using sophisticated Hall probes that are integrated with AFM cantilevers. However it is very difficult to micro fabricate these sensors. In this work, we have eliminated the difficulty in the cantilever-Hall probe integration process, just by gluing a Hall Probe chip to a quartz crystal tuning fork force sensor. The Hall sensor chip is simply glued at the end of a 32.768 kHz or 100 kHz Quartz crystal, which is used as force sensor. An LT-SHPM system is used to scan the samples. The sensor assembly is dithered at the resonance frequency using a digital Phase Locked Loop circuit and frequency shifts are used for AFM tracking. SHPM electronics is modified to detect AFM topography and the frequency shift, along with the magnetic field image. Magnetic domains and topography of an Iron Garnet thin film crystal, NdFeB demagnetised magnet and hard disk samples are presented at room temperature. The performance is found to be comparable with the SHPM using STM feedback.

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Lenk, Daniel, Vladimir I. Zdravkov, Jan-Michael Kehrle, Günter Obermeier, Aladin Ullrich, Roman Morari, Hans-Albrecht Krug von Nidda, et al. "Thickness dependence of the triplet spin-valve effect in superconductor–ferromagnet–ferromagnet heterostructures." Beilstein Journal of Nanotechnology 7 (July 4, 2016): 957–69. http://dx.doi.org/10.3762/bjnano.7.88.

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Background: In nanoscale layered S/F1/N/F2/AF heterostructures, the generation of a long-range, odd-in-frequency spin-projection one triplet component of superconductivity, arising at non-collinear alignment of the magnetizations of F1 and F2, exhausts the singlet state. This yields the possibility of a global minimum of the superconducting transition temperature T c, i.e., a superconducting triplet spin-valve effect, around mutually perpendicular alignment. Results: The superconducting triplet spin valve is realized with S = Nb a singlet superconductor, F1 = Cu41Ni59 and F2 = Co ferromagnetic metals, AF = CoO x an antiferromagnetic oxide, and N = nc-Nb a normal conducting (nc) non-magnetic metal, which serves to decouple F1 and F2. The non-collinear alignment of the magnetizations is obtained by applying an external magnetic field parallel to the layers of the heterostructure and exploiting the intrinsic perpendicular easy-axis of the magnetization of the Cu41Ni59 thin film in conjunction with the exchange bias between CoO x and Co. The magnetic configurations are confirmed by superconducting quantum interference device (SQUID) magnetic moment measurements. The triplet spin-valve effect has been investigated for different layer thicknesses, d F1, of F1 and was found to decay with increasing d F1. The data is described by an empirical model and, moreover, by calculations using the microscopic theory. Conclusion: The long-range triplet component of superconducting pairing is generated from the singlet component mainly at the N/F2 interface, where the amplitude of the singlet component is suppressed exponentially with increasing distance d F1. The decay length of the empirical model is found to be comparable to twice the electron mean free path of F1 and, thus, to the decay length of the singlet component in F1. Moreover, the obtained data is in qualitative agreement with the microscopic theory, which, however, predicts a (not investigated) breakdown of the triplet spin-valve effect for d F1 smaller than 0.3 to 0.4 times the magnetic coherence length, ξF1.

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Federici, F., and J. M. F. Gunn. "Magnetic instabilities in thin non-planar ferromagnetic films." Journal of Magnetism and Magnetic Materials 226-230 (May 2001): 1607–9. http://dx.doi.org/10.1016/s0304-8853(00)01036-2.

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ZHONG ZHI-YONG, LAN ZHONG-WEN, ZHANG HUAI-WU, LIU YING-LI, and WANG HAO-CAI. "COMPUTATION ON GIANT MAGNETO-IMPEDANCE EFFECTS IN FERROMAGNETIC/NON-FERROMAGNETIC/FERROMAGNETIC LAYERED THIN FILMS." Acta Physica Sinica 50, no. 8 (2001): 1610. http://dx.doi.org/10.7498/aps.50.1610.

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Voltairas, P. A., D. I. Fotiadis, and C. V. Massalas. "Non-uniform magnetization reversal in stressed thin ferromagnetic films." Journal of Magnetism and Magnetic Materials 213, no. 1-2 (April 2000): 43–50. http://dx.doi.org/10.1016/s0304-8853(99)00567-3.

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Li, Shan Dong, Feng Xu, Ming Liu, Yi Hu, Jian Peng Wu, Xin Le Cai, Jie Qiu, Jian Hua Lin, and Jenq Gong Duh. "Effect of the Thickness of Cr Interlayer on the High-Frequency Characteristics of FeCoTa/Cr/FeCoTa Multilayers." Advanced Materials Research 287-290 (July 2011): 1356–59. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.1356.

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The effect of non-ferromagnetic Cr interlayer on the high-frequency ferromagnetic properties (HFFMPs) was investigated by use of FeCoTa/Cr/ FeCoTa triple layered films. In conventional thought, the metal interlayer gives rise to a high eddy current loss and therefore a deteriorated HFFMP. However, it is found that HFFMPs depend on the thickness of Cr interlayer. The HFFPMs are improved by Cr-interlayer with a thickness less than 12 nm (sample C1). Comparing with the Cr-interlayer-free FeCoHf single layered film (sample C0), the magnetic anisotropy field of C1 dramatically increases from 185 Oe for C0 to 558 Oe for C1. As a consequence, a high ferromagnetic resonance frequency over than 3 GHz is achieved for sample C1. When the thickness of Cr-interlayer is more than 120 nm (C2), the HFFMPs are reduced due to the increase of eddy current loss and magnetic decoupling between the ferromagnetic layers.

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Mokrani, A. "Non-ferromagnetic solutions for Fe thin films on Co(001)." Journal of Magnetism and Magnetic Materials 198-199, no. 1-3 (June 1, 1999): 561–63. http://dx.doi.org/10.1016/s0304-8853(98)01217-7.

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Zhang, Weiwei, Zhanghua Chen, Vladimir I. Belotelov, and Yujun Song. "Longitudinal Magneto-Optical Kerr Effect of Nanoporous CoFeB and W/CoFeB/W Thin Films." Coatings 12, no. 2 (January 20, 2022): 115. http://dx.doi.org/10.3390/coatings12020115.

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Nanoporous Co40Fe40B20 (CoFeB) and sandwich tungsten (W)/CoFeB/W thin films were fabricated via an anodic aluminum oxide (AAO) template-assisted magneto sputtering process. Their thickness-dependent magneto-optical Kerr effect (MOKE) hysteresis loops were investigated for enhanced Kerr rotation. Control of the Kerr null points of the polarized reflected light can be realized via the thicknesses of the CoFeB layers and W layers. Simulation of the thickness-dependent phase difference change by the finite element method reveals the existence of the two Kerr null points for W/CoFeB/W thin films, matching the experimental result very well. However, there are two additional Kerr null points for pure CoFeB thin films according to the simulation by comparing with the experimental result (only one). Theoretical analysis indicates that the different Kerr null points between the experimental result and the simulation are mainly due to the enhanced inner magnetization in the ferromagnetic CoFeB layer with the increased thickness, which is usually omitted in the simulation. Clearly, the introduction of non-ferromagnetic W layers can experimentally regulate the Kerr null points of ferromagnetic thin films. Moreover, construction of W/CoFeB/W sandwich thin films can greatly increase the highest magneto-optical susceptibility and the saturated Kerr rotation angle when compared with CoFeB thin films of the same thickness.

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Jaroenjittichai, Atchara Punya, and Yongyut Laosiritaworn. "The competitive effect of non-magnetic defect and films thickness on the ferromagnetic critical temperature in Ising thin-films." MATEC Web of Conferences 249 (2018): 01008. http://dx.doi.org/10.1051/matecconf/201824901008.

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In this work, Monte Carlo simulation was employed to investigate the competitive effect of non-magnetic defects and the thickness on the ferromagnetic behavior of Ising spins in a reduced geometry, i.e. thin-films. The magnetic properties were investigated as functions of temperature, defect concentration, and films’ thickness, especially in the ferromagnetic phase transition region. The finite size scaling was performed via the fourth order cumulant of the magnetization to extract the critical temperatures. From the results, the extracted critical temperatures agree well with previous theoretical investigation, where applicable. With increasing concentration of the nonmagnetic defects, the Ising phase-transition-point slightly shifts towards lower temperature, while the increase of films thickness enhances the critical temperature value. Being confirmed by the main-effect-plot analysis, the increase in thickness has much greater influences on the critical temperature than that of the defect concentration, which could be described in term of the average ferromagnetic interaction spin. As the role of the defect is negligence in the range of considered defect concentration (up to ten percent), it therefore suggests that the preparation of ferromagnetic films can be done in normal operating condition where defects usually occur. It may be not economically worth to aim for the perfectly smooth films when the associated application operates at temperatures away from the critical point.

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Kostylev, M. "Non-reciprocity of dipole-exchange spin waves in thin ferromagnetic films." Journal of Applied Physics 113, no. 5 (February 7, 2013): 053907. http://dx.doi.org/10.1063/1.4789962.

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Hütten, Andreas, and Gareth Thomas. "Materials science aspects in designing giant magnetoresistance in heterogeneous Cu1-xCox thin films." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 1018–19. http://dx.doi.org/10.1017/s0424820100150927.

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The recent discovery of giant magnetoresistance (GMR) in heterogeneous Cu1-xCox thin films has brought new insights in the phenomenon of GMR, which was previously believed to be restricted to multilayered structures only. Subsequent theoretical analyses of GMR in this new materials class have shown that GMR is mainly controlled by the mean radius and the volume fraction of single domain ferromagnetic particles. In addition to these parameters, the mean free path for electron in the non-magnetic matrix as well as coherency between particles and matrix are influencing the amplitude of GMR. Clearly, the key to increase the amplitude of GMR is to determine the decomposition kinetics and from which to optimize the single domain ferromagnetic Co particle size distribution in heterogeneous Cu1-xCox thin films.Cu81Col9 films, 50 nm in thickness, have been deposited by dc magnetron sputtering from separate Cu and Co targets onto 30 nm thick silicon nitride electron transparent grids.

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Kiseliev, V. V., and A. P. Tankeyev. "Non-local dynamics of weakly nonlinear spin excitations in thin ferromagnetic films." Journal of Physics: Condensed Matter 8, no. 49 (December 2, 1996): 10219–29. http://dx.doi.org/10.1088/0953-8984/8/49/013.

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Portavoce, A., E. Assaf, C. Alvarez, M. Bertoglio, R. Clérac, K. Hoummada, C. Alfonso, et al. "Ferromagnetic MnCoGe thin films produced via magnetron sputtering and non-diffusive reaction." Applied Surface Science 437 (April 2018): 336–46. http://dx.doi.org/10.1016/j.apsusc.2017.12.151.

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Wu, Y., Z. Tang, Y. Xu, and B. Zhang. "Measuring complex permeability of ferromagnetic thin films using non-50 shorted microstrip method." Electronics Letters 46, no. 12 (2010): 848. http://dx.doi.org/10.1049/el.2010.0464.

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Демидов, В. В., and А. Е. Мефёд. "Возможности магнитного псевдорезонанса в изучении тонких ферромагнитных пленок с одноосной магнитной анизотропией." Журнал технической физики 89, no. 1 (2019): 72. http://dx.doi.org/10.21883/jtf.2019.01.46965.55-18.

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AbstractPossibilities of magnetic pseudoresonance (a non-resonance peak of magnetic susceptibility) were studied and compared with the ferromagnetic resonance (FMR) in measuring the parameters of thin ferromagnetic films with in-plane uniaxial magnetic anisotropy. The measurements were conducted with two characteristic samples of ferromagnetic films showing this effect. A Q -meter operating at a frequency near 300 MHz (for pseudoresonance) and a standard X -band magnetic resonance spectrometer (for FMR) were used. The Q -meter working at 300 MHz was shown to detect reliably the magnetic pseudoresonance in both epitaxial and polycrystalline films. It was found that the accuracy of determination of the magnetic anisotropy field and orientation of the easy magnetization axis provided by the pseudoresonance method is as good as with FMR, and in some cases the pseudoresonance method gives additional information.

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Kaneko, Kentaro, Kazuaki Akaiwa, and Shizuo Fujita. "Crystal Structure of Non-Doped and Sn-Doped α-(GaFe)2O3 Thin Films." MRS Proceedings 1494 (2013): 147–52. http://dx.doi.org/10.1557/opl.2013.5.

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ABSTRACTCorundum structured α-(GaFe)2O3 alloy thin films were obtained on c-plane sapphire substrates by the mist chemical vapor deposition method. Wide range of X-ray diffraction 2θ/θ scanning measurements indicated that these crystals were epitaxially grown on c-plane sapphire substrates and these are no other crystal oriented phase. The cross-sectional and plane-view transmission electron microscope images showed the growth along the c-axis of α-(GaFe)2O3 thin films on sapphire substrates, forming joint of columnar structure. The non-doped α-(GaFe)2O3 thin films showed ferromagnetic properties at 300 K, though the origin of ferromagnetism still remained unresolved. In order to enhance the spin-carrier interaction, Sn doped α-(GaFe)2O3 alloy thin films were fabricated on c-plane sapphire substrates. X-ray diffraction 2θ/θ and ω scanning measurement results indicated that the highly-crystalline films were epitaxially grown on substrates in spite of the Sn-doping.

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Li, Hang, Xinhui Zhang, Xinyu Liu, Margaret Dobrowolska, and Jacek Furdyna. "Ultrafast Modulation of Magnetization Dynamics in Ferromagnetic (Ga, Mn)As Thin Films." Applied Sciences 8, no. 10 (October 11, 2018): 1880. http://dx.doi.org/10.3390/app8101880.

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Magnetization precession induced by linearly polarized optical excitation in ferromagnetic (Ga,Mn)As was studied by time-resolved magneto-optical Kerr effect measurements. The superposition of thermal and non-thermal effects arising from the laser pulses complicates the analysis of magnetization precession in terms of magnetic anisotropy fields. To obtain insight into these processes, we investigated compressively-strained thin (Ga,Mn)As films using ultrafast optical excitation above the band gap as a function of pulse intensity. Data analyses with the gyromagnetic calculation based on Landau-Lifshitz-Gilbert equation combined with two different magneto-optical effects shows the non-equivalent effects of in-plane and out-of-plane magnetic anisotropy fields on both the amplitude and the frequency of magnetization precession, thus providing a handle for separating the effects of non-thermal and thermal processes in this context. Our results show that the effect of photo-generated carriers on magnetic anisotropy constitutes a particularly effective mechanism for controlling both the frequency and amplitude of magnetization precession, thus suggesting the possibility of non-thermal manipulation of spin dynamics through pulsed laser excitations.

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Agarwal, Piyush, Yingshu Yang, James Lourembam, Rohit Medwal, Marco Battiato, and Ranjan Singh. "Terahertz spintronic magnetometer (TSM)." Applied Physics Letters 120, no. 16 (April 18, 2022): 161104. http://dx.doi.org/10.1063/5.0079989.

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A ferromagnetic metal consists of localized electrons and conduction electrons coupled through strong exchange interaction. Together, these localized electrons contribute to the magnetization of the system, while conduction electrons lead to the formation of spin and charge current. Femtosecond out of equilibrium photoexcitation of ferromagnetic thin films generates a transient spin current at ultrafast timescales that have opened a route to probe magnetism offered by the conduction electrons. In the presence of a neighboring heavy metal layer, the non-equilibrium spin current is converted into a pulsed charge current and gives rise to terahertz (THz) emission. Here, we propose and demonstrate a tool known as the terahertz spintronic magnetometry. The hysteresis loop obtained by sweeping terahertz (THz) pulse amplitude as a function of the magnetic field is in excellent agreement with the vibrating-sample magnetometer measurements. Furthermore, a modified transfer-matrix method employed to model the THz propagation within the heterostructure theoretically elucidates a linear relationship between the THz pulse amplitude and sample magnetization. The strong correlation, thus, reveals spintronic terahertz emission as an ultrafast magnetometry tool with reliable in-plane magnetization detection, highlighting its technological importance in the characterization of ferromagnetic thin-films through terahertz spintronic emission spectroscopy.

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Beirle, S., and K. Seemann. "Non-contact high-frequency measurements of mechanically loaded ferromagnetic thin films: An alternative approach for torque sensors." Sensors and Actuators A: Physical 301 (January 2020): 111788. http://dx.doi.org/10.1016/j.sna.2019.111788.

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Hashim, H., S. P. Singh, L. V. Panina, F. A. Pudonin, I. A. Sherstnev, S. V. Podgornaya, and I. Shpetnyy. "Optical and magnetic properties of Al/NiFe and Al/Ge/NiFe nanosized films." EPJ Web of Conferences 185 (2018): 04014. http://dx.doi.org/10.1051/epjconf/201818504014.

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Nanosized films with ferromagnetic layers are widely used in nanoelectronics, sensor systems and telecommunication. The physical and magnetic properties of nanolayers may significantly differ from those known for bulk materials due to fine crystalline structure, influence of interfaces, roughness, and diffusion. In this work, we are employing a spectral ellipsometry method, magneto-optical Kerr magnetometry and VSM to investigate the impact of layer thickness on the optical constants and magnetization processes for two and three layer films of the type Al/NiFe/sitall, Al/Ge/NiFe/sitall on sitall substrate for different thickness of the upper Al layers. The refractive indexes of two layer films are well resolved by spectral ellipsometry demonstrating their good quality. Modelling data for three-layer films show considerable discrepancy with the experiment, which can be related to a stronger influence of interfaces. The magnetization processes of two-layer films weakly depend on the type and thickness of the upper non-ferromagnetic layers. However, the coercivity of three layer films may significantly change with the thickness of the upper layer: more than twice when the thickness of Al layer increases from 4 to 20 nm.

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Bennett, Steven P., Samuel W. LaGasse, Marc Currie, Olaf Van’t Erve, Joseph C. Prestigiacomo, Cory D. Cress, and Syed B. Qadri. "N+ Irradiation and Substrate-Induced Variability in the Metamagnetic Phase Transition of FeRh Films." Coatings 11, no. 6 (May 31, 2021): 661. http://dx.doi.org/10.3390/coatings11060661.

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Metamagnetic FeRh has been the focus of numerous studies for its highly unique antiferromagnetic (AF) to ferromagnetic (FM) metamagnetic transition. While this phase transition usually occurs above room temperature (often Tc > 400 K), both ion irradiation and strained epitaxial growth have been used to bring it to applicable temperatures. Nevertheless, cross sample variability is pervasive in these studies. Here we explore the optical and magnetic properties of 35 nm thick FeRh grown by magnetron sputter deposition simultaneously on two different single crystal substrates: epitaxially on MgO (001) and highly strained with large lattice mismatch on Al2O3 (1000). We then irradiate the epitaxial film with 5 keV N+ ions to introduce disorder (and to a lesser extent, modify chemical composition) without effecting the surface morphology. We find that the phase-transitional properties of both films are strikingly different due to the large lattice mismatch, despite being grown in tandem with nominally identical growth conditions including Fe/Rh stoichiometry, pressure, and temperature. We observe that N+ implantation lowers Tc by ~60 K, yielding a sample with nominally the same transition temperature as the non-epitaxial film on sapphire, yet with a significantly increased magnetic moment, a larger magnetization change and a more abrupt transition profile. We attribute these differences to the Volmer-Weber type growth mode induced by the sapphire substrate and the resulting rougher surface morphology.

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Bakhmetiev, Maxim, Artem Talantsev, Alexandr Sadovnikov, and Roman Morgunov. "Modulation of interfacial magnetic relaxation timeframes by partially uncoupled exchange bias." Journal of Physics D: Applied Physics 55, no. 10 (December 6, 2021): 105001. http://dx.doi.org/10.1088/1361-6463/ac3ce7.

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Abstract A set of partially uncoupled NiFe/Cu/IrMn exchange biased thin films with variable thickness of non-magnetic Cu spacer is characterized by ferromagnetic resonance (FMR) and Brillouin light scattering (BLS) techniques applied complementary to reveal time-scale dependent effects of uncoupling between ferromagnetic and antiferromagnetic layers on high-frequency magnetization dynamics. The results correlate with interfacial grain texture variations and static magnetization behavior. Two types of crystalline phases with correlated microwave response are revealed at the ferro–antiferromagnet interface in NiFe/Cu/IrMn thin films. The 1st phase forms well-textured NiFe/IrMn grains with NiFe (111)/IrMn (111) interface. The 2nd phase consists of amorphous NiFe/IrMn grains. Intercalation of NiFe/IrMn by Cu clusters results in relaxation of tensile strains at the NiFe/IrMn interface leading to larger size of grains in both the NiFe and IrMn layers. The contributions of well-textured and amorphous grains to the high-frequency magnetization reversal behavior are distinguished by FMR and BLS techniques. Generation of a spin-wave mode is revealed in the well-textured phase, whereas microwave response of the amorphous phase is found to originate from magnetization rotation dominated by a rotatable magnetic anisotropy term. Under fixed FMR frequency, the increase of Cu thickness results in higher magnetization rotation frequencies in the amorphous grains.

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Huang, Zhao Lin, Bin Peng, Ke Tan, Wen Xu Zhang, and Wan Li Zhang. "Effects of Sintering Temperature on the Barium Hexaferrite Thick Films Prepared by Screen Printing Method." Materials Science Forum 687 (June 2011): 51–54. http://dx.doi.org/10.4028/www.scientific.net/msf.687.51.

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In this paper, barium hexaferrite thick films with thickness of 80 microns were prepared on alumina substrates by screen printing method for applications in self-biased planar microwave devices. The influences of sintering temperature on the microstructures and magnetic properties of barium ferrite (BaM) thick films were investigated. The results show that with the increase of sintering temperature, the grain size increases and the porosity of the BaM thick films decreases. When the sintering temperature is below 1200 °C, the BaM thick films show magnetic properties with coercive force of about 3.5 kOe and magnetization at 20 KOe (4πM20kOe) of about 1750 Gs. When the sintering temperature is greater than 1200 °C, the magnetic properties deteriorate remarkably and exhibit a coercive force of 0.4 kOe and 4πM20kOe of about 480 Gs due to the over-sintering and diffusion of Al atoms into the BaM thick films. A new non-ferromagnetic phase Al13Ba7 is formed, which is detected by XRD.

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Herklotz, A., M. D. Biegalski, H. M. Christen, E. J. Guo, K. Nenkov, A. D. Rata, L. Schultz, and K. Dörr. "Strain response of magnetic order in perovskite-type oxide films." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 372, no. 2009 (February 28, 2014): 20120441. http://dx.doi.org/10.1098/rsta.2012.0441.

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The role of elastic strain for magnetoelectric materials and devices is twofold. It can induce ferroic orders in thin films of otherwise non-ferroic materials. On the other hand, it provides the most exploited coupling mechanism in two-phase magnetoelectric materials and devices today. Complex oxide films (perovskites, spinels) are promising for both routes. The strain control of magnetic order in complex oxide films is a young research field, and few ab initio simulations are available for magnetic order in dependence on lattice parameters and lattice symmetry. Here, an experimental approach for the evaluation of how elastic strain in thin epitaxial films alters their magnetic order is introduced. The magnetic films are grown epitaxially in strain states controlled by buffer layers onto piezoelectric substrates of 0.72Pb(Mg 1/3 Nb 2/3 )O 3 –0.28PbTiO 3 (001). As an example, the strain dependence of the ordered magnetic moment of SrRuO 3 has been investigated. At a tensile strain level of approximately 1%, SrRuO 3 is tetragonal, and biaxial elastic strain induces a pronounced suppression of the ordered magnetic moment. As a second example, a strain-driven transition from a ferromagnetic to a magnetically disordered phase has been observed in epitaxial La 0.8 Sr 0.2 CoO 3 films.

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Millo, Oded, and Gad Koren. "What can Andreev bound states tell us about superconductors?" Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 376, no. 2125 (June 25, 2018): 20140143. http://dx.doi.org/10.1098/rsta.2014.0143.

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Zero-energy Andreev bound states, which manifest themselves in the tunnelling spectra as zero-bias conductance peaks (ZBCPs), are abundant at interfaces between superconductors and other materials and on the nodal surface of high-temperature superconductors. In this review, we focus on the information such excitations can provide on the properties of superconductor systems. First, a general introduction to the physics of Andreev bound states in superconductor/normal metal interfaces is given with a particular emphasis on why they appear at zero energy in d -wave superconductors. Then, specific spectroscopic tunnelling studies of thin films, bilayers and junctions are described, focusing on the corresponding ZBCP features. Scanning tunnelling spectroscopy (STS) studies show that the ZBCPs on the c -axis YBa 2 Cu 3 O 7− δ (YBCO) films are correlated with the surface morphology and appear only in proximity to (110) facets. STS on c -axis La 1.88 Sr 0.12 CuO 4 (LSCO) films exhibiting the 1/8 anomaly shows spatially modulated peaks near zero bias associated with the anti-phase ordering of the d -wave order parameter predicted at this doping level. ZBCPs were also found in micrometre-size edge junctions of YBCO/SrRuO 3 /YBCO, where SrRuO 3 is ferromagnetic. Here, the results are consistent with a crossed Andreev reflection effect (CARE) at the narrow domain walls of the SrRuO 3 . ZBCPs measured in STS studies of manganite/cuprate bilayers could not be attributed to CARE because the manganite's domain wall is much larger than the coherence length in YBCO, and instead are attributed to proximity-induced triplet-pairing superconductivity with non-conventional symmetry. And finally, ZBCPs found in junctions of non-intentionally doped topological insulator films of Bi 2 Se 3 and the s -wave superconductor NbN are attributed to proximity-induced p x + i p y triplet order parameter in the topological material. This article is part of the theme issue ’Andreev bound states’.

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Orgiani, Pasquale, Alice Galdi, Darrell G. Schlom, and Luigi Maritato. "Normal-State Transport Properties of Infinite-Layer Sr1−xLaxCuO2 Electron-Doped Cuprates in Optimal- and Over-Doped Regimes." Nanomaterials 12, no. 10 (May 17, 2022): 1709. http://dx.doi.org/10.3390/nano12101709.

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Transport properties of electron-doped cuprate Sr1−xLaxCuO2 thin films have been investigated as a function of doping. In particular, optimal- and over-doped samples were obtained by tuning the Sr:La stoichiometric ratio. Optimal-doped samples show a non-Fermi liquid behavior characterized by linear dependence of the resistivity from room temperature down to intermediate temperature (about 150–170 K). However, by approaching temperatures in the superconducting transition, a Fermi-liquid behavior-characterized by a T2-scaling law-was observed. Once established, the transition from a linear-T to a quadratic-T2 behavior was successfully traced back in over-doped samples, even occurring at lower temperatures. In addition, the over-doped samples show a crossover to a linear-T to a logarithmic dependence at high temperatures compatible with anti-ferromagnetic spin fluctuations dominating the normal state properties of electron-doped cuprates.

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Navas, David, David G. Trabada, and Manuel Vázquez. "Nanoimprinted and Anodized Templates for Large-Scale and Low-Cost Nanopatterning." Nanomaterials 11, no. 12 (December 17, 2021): 3430. http://dx.doi.org/10.3390/nano11123430.

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Nanopatterning to fabricate advanced nanostructured materials is a widely employed technology in a broad spectrum of applications going from spintronics and nanoelectronics to nanophotonics. This work reports on an easy route for nanopatterning making use of ordered porous templates with geometries ranging from straight lines to square, triangular or rhombohedral lattices, to be employed for the designed growth of sputtered materials with engineered properties. The procedure is based on large-scale nanoimprinting using patterned low-cost commercial disks, as 1-D grating stamps, followed by a single electrochemical process that allows one to obtain 1-D ordered porous anodic templates. Multiple imprinting steps at different angles enable more complex 2-D patterned templates. Subsequently, sputtering facilitates the growth of ferromagnetic antidot thin films (e.g., from 20 to 100 nm Co thick layers) with designed symmetries. This technique constitutes a non-expensive method for massive mold production and pattern generation avoiding standard lithographical techniques. In addition, it overcomes current challenges of the two-stage electrochemical porous anodic alumina templates: (i) allowing the patterning of large areas with high ordering and/or complex antidot geometries, and (ii) being less-time consuming.

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45

Marchal, Nicolas, Tristan da Câmara Santa Clara Gomes, Flavio Abreu Araujo, and Luc Piraux. "Giant Magnetoresistance and Magneto-Thermopower in 3D Interconnected NixFe1−x/Cu Multilayered Nanowire Networks." Nanomaterials 11, no. 5 (April 27, 2021): 1133. http://dx.doi.org/10.3390/nano11051133.

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The versatility of the template-assisted electrodeposition technique to fabricate complex three-dimensional networks made of interconnected nanowires allows one to easily stack ferromagnetic and non-magnetic metallic layers along the nanowire axis. This leads to the fabrication of unique multilayered nanowire network films showing giant magnetoresistance effect in the current-perpendicular-to-plane configuration that can be reliably measured along the macroscopic in-plane direction of the films. Moreover, the system also enables reliable measurements of the analogous magneto-thermoelectric properties of the multilayered nanowire networks. Here, three-dimensional interconnected NixFe1−x/Cu multilayered nanowire networks (with 0.60≤x≤0.97) are fabricated and characterized, leading to large magnetoresistance and magneto-thermopower ratios up to 17% and −25% in Ni80Fe20/Cu, respectively. A strong contrast is observed between the amplitudes of magnetoresistance and magneto-thermoelectric effects depending on the Ni content of the NiFe alloys. In particular, for the highest Ni concentrations, a strong increase in the magneto-thermoelectric effect is observed, more than a factor of 7 larger than the magnetoresistive effect for Ni97Fe3/Cu multilayers. This sharp increase is mainly due to an increase in the spin-dependent Seebeck coefficient from −7 µV/K for the Ni60Fe40/Cu and Ni70Fe30/Cu nanowire arrays to −21 µV/K for the Ni97Fe3/Cu nanowire array. The enhancement of the magneto-thermoelectric effect for multilayered nanowire networks based on dilute Ni alloys is promising for obtaining a flexible magnetic switch for thermoelectric generation for potential applications in heat management or logic devices using thermal energy.

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Hu, Xiangyi, Yang Bu, and Jianhua Zhang. "A nonlinear magneto-elastoplastic coupling model based on Jiles–Atherton theory of ferromagnetic materials." Journal of Physics D: Applied Physics 55, no. 16 (January 28, 2022): 165005. http://dx.doi.org/10.1088/1361-6463/ac42f9.

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Abstract As seen in the Jiles–Atherton (J–A) model and its modified form, the linear relationship between the magnetization coefficient and the stress deviates significantly from the experimental results. It is necessary to introduce many parameters that are difficult to obtain or unknown to describe the effect of elastoplastic deformation on magnetization or hysteresis, such as shape coefficient, pinning coefficient, and molecular field coefficient. In this paper, a new nonlinear magneto-elastoplastic model for ferromagnetic materials is established based on the magneto-mechanical coupling effect, and both the sixth-order term of magnetization and the nonlinear equation of the magnetization coefficient are introduced into the magnetostriction equation. In the models established in this paper, the elastoplastic deformation equivalent magnetic field is introduced into the effective magnetic field, and the Frohlich–Kennelly equation is used to describe the anhysteretic magnetization. After comparing the prediction results of different models with the available experimental results, it is observed that the proposed model in this paper exhibits superior prediction ability for magnetostrictive strain, magnetization, and hysteresis phenomena under different stresses. This paper has also analyzed the mechanism of the effect of elasto-plastic loading and residual stress on the hysteresis in different models as well as the differences between them. The determination coefficient of the proposed model in this paper is closer to 1, which is better than the existing models, indicating that it has a better fitting effect and is of great significance to the development of quantitative non-destructive testing technology.

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Sakuda, Masahiro, Hiroyasu Yamahara, Hitoshi Tabata, and Munetoshi Seki. "Control of Magnetic Properties of Barium Ferrite Thin Films With Unusual Valence Fe." Frontiers in Materials 8 (September 9, 2021). http://dx.doi.org/10.3389/fmats.2021.732676.

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Thin films of BaFe1-xMxO3 (M = Hf, Zr, and Ce; 0.0 ≤ x ≤ 0.75) were fabricated using pulsed laser deposition and their magnetic properties were investigated. X-ray diffraction analysis indicated that oxygen-deficient BaFeOx (x < 3.0) with a monoclinic structure was formed when the deposition was conducted using a non-substituted target (x = 0.0). The as-grown BaFeOx films were converted into fully oxidized BaFeO3 with a perovskite structure by low-temperature oxidation in an ozone atmosphere. In contrast, the as-deposited films of Hf, Zr, and Ce-substituted films exhibited a perovskite structure, and their crystallinity did not change after low-temperature ozone annealing. The magnetic transition temperature Tc of the BaFeO3 film was 115 K, whereas the substituted BaFeO3 films showed ferromagnetic behavior even at 300 K. These results can be attributed to the weakening of the antiferromagnetic super-exchange coupling among Fe ions owing to the lattice expansion in the substituted BaFeO3. In addition, the magnetization of the films was found to increase with the decreasing ionic ratio of Fe4+/Fe3+, suggesting that the inherent carrier-induced ferromagnetic interaction is dominant in the films.

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Hinckley, A., R. K. Gupta, P. K. Kahol, and K. Ghosh. "Magnetization Effects in bulk YFeO3 and their dependency on electric field strength and temperature as a basis for thin film investigation of Multiferroic Technology." MRS Proceedings 1292 (2011). http://dx.doi.org/10.1557/opl.2011.242.

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ABSTRACTMultiferroics, the study of materials which possess ferromagnetic and ferroelectric ordering in a single phase, has become an area of prominent research. Moreover, this behavior has been extensively studied in materials which possess a perovskite crystal structure such as BiFeO3 and YMnO3. Due to their weak saturation magnetic moment, many rare-earth orthoferrites are currently of extreme interest. Utilizing a solid-state reaction between Y2O3 and Fe2O3 we have developed the rare-earth orthoferrite YFeO3 and conducted a bulk material study to determine this material’s availability for thin film multiferroic research. The absence of Y2O3 and Fe2O3 impurities was confirmed using Copper-Kα XRD. Examination of the dependence of the magnetization M on the temperature T was conducted to determine the reliability of multiferroic behavior across varying temperatures in conjunction with the investigation of the dependence of M on the electric field strength H. Results clearly display ferromagnetic behavior in our bulk material, providing ample evidence that our bulk material is an excellent candidate for thin film studies. Future studies on multiferroic YFeO3 thin films grown via pulsed laser deposition on Lanthanum Aluminate substrates will be conducted. Detailed data will be provided via XRD and SQUID to confirm magnetic properties while impurities are non-existent in our thin films.

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Hu, Zhongqiang, Xinjun Wang, Tianxiang Nan, Ziyao Zhou, Beihai Ma, Xiaoqin Chen, John G. Jones, et al. "Non-Volatile Ferroelectric Switching of Ferromagnetic Resonance in NiFe/PLZT Multiferroic Thin Film Heterostructures." Scientific Reports 6, no. 1 (September 1, 2016). http://dx.doi.org/10.1038/srep32408.

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Wang, J. P., Y. Zhao, T. J. Zhou, J. T. L. Thong, and T. C. Chong. "Magnetic Nanostructures Produced By Electron Beam Direct Writing." MRS Proceedings 777 (2003). http://dx.doi.org/10.1557/proc-777-t4.13.

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AbstractWe present a method of direct magnetic patterning of nonmagnetic CoC and CoTaC films by electron irradiation-induced nano-scale phase transition. CoxC1-x (0.4<X<0.8) films were prepared by co-sputtering. The as-deposited films with Co concentration less than 60% are amorphous and non-ferromagnetic. All films become ferromagnetic after annealing. Doping Ta into the CoC films can enhance the segregation of Co and C and therefore reduce the phase transition temperature. It is found that the magnetic properties of annealed (Co60C40)97Ta3 films are much better than that of annealed Co60C40 films at the same annealing condition. Magnetic nano-patterning (dot/line array) of the as-deposited CoC and Co(TaC) films was realized by subjecting them to electron irradiation using a focused 30keV electron beam with a current of 7.1 nA and dwell time per dot of 0.75 to 15.2 seconds. A 250nm magnetic dot/line array was produced by this method. It was also found that the time required to magnetically pattern non-magnetic (Co60C40)97Ta3 thin films (0.75 seconds) is much shorter than that required for Co60C40 films (3.8 seconds). The present method of magnetically patterning a nonmagnetic film has the potential application for nanoscale solid magnetic devices.

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Journal articles on the topic 'Non-ferromagnetic thin film'

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