Journal articles: 'Non-stoichiometric Full Heusler Alloys'

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Govind, Bal, Purnima Bharti, Sahiba Bano, Ashish Kumar, Satyendra Singh, and V. P. S. Awana. "Disorder Induced Magnetic Behavior of Non-Stoichiometric Co0.75Mn0.5Fe0.75Si Full-Heusler Alloy." Journal of Superconductivity and Novel Magnetism 35, no. 2 (November 7, 2021): 445–53. http://dx.doi.org/10.1007/s10948-021-06076-6.

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Lukoyanov, Alexey V., Elena I. Shreder, and Vyacheslav V. Marchenkov. "Electronic Structure of the Non-Stoichiometric L21-Type Mn1.75Co1.25Al Heusler Alloy." Materials Science Forum 1093 (July 21, 2023): 21–26. http://dx.doi.org/10.4028/p-ej1mdu.

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Theoretical ab initio calculations of the electronic structure were performed for the non-stoichiometric Mn1.75Co1.25Al Heusler alloy and compared with the electronic structure of the stoichiometric Mn2CoAl full Heusler alloy. Both compounds are assumed to have the L21-type crystal structure in the calculations, the non-stoichiometry is taken into account as a substitution of a Mn atom in a supercell. The calculation for the non-stoichiometric composition of Mn1.75Co1.25Al showed that taking non-stoichiometry into account leads to a decrease of the total magnetic moment. In comparison with the inverse type of Mn2CoAl, in both Mn2CoAl and Mn1.75Co1.25Al, the metallic type of the total density of states at the Fermi level was obtained in our calculations. In Mn1.75Co1.25Al, the total density of electronic states is found to be close to the one of the stoichiometric Mn2CoAl alloy in the majority spin projection, and in the minority spin projection spin polarization leads to the formation of the more intense peaks due to the appearance of an additional non-stoichiometric cobalt with a significant magnetic moment, as well as an increase in the magnetic moments of the other magnetic ions.

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Srivastava, Vijay, and Kanwal Preet Bhatti. "Ferromagnetic Shape Memory Heusler Alloys." Solid State Phenomena 189 (June 2012): 189–208. http://dx.doi.org/10.4028/www.scientific.net/ssp.189.189.

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Although Heusler alloys have been known for more than a century, but since the last decade there has been a quantum jump in research in this area. Heusler alloys show remarkable properties, such as ferromagnetic shape memory effect, magnetocaloric effect, half metallicity, and most recently it has been shown that it can be used for direct conversion of heat into electricity. Heusler alloys Ni-Mn-Z (Z=Ga, Al, In, Sn, Sb), show a reversible martensitic transformation and unusual magnetic properties. Other classes of intermetallic Heusler alloy families that are half metallic (such as the half Heusler alloys Ni-Mn-Sb and the full Heusler alloy Co2MnGe) are attractive because of their high Curie temperature and structural similarity to binary semiconductors. Unlike Ni-Mn-Ga, Ni-Mn-In and Ni-Mn-Sn transform from ferromagnetic austenite to non-ferromagnetic martensite. As is consistent with the Clausius-Clapeyron equation, the martensitic phase transformation can be manipulated by a magnetic field, leading to possible applications of these materials enabling the magnetic shape memory effect, energy conversion and solid state refrigeration. In this paper, we summarize the salient features of Heusler alloys, like the structure, magnetic properties and potential application of this family of alloys in industry.

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Özdemir, Evren G., and Semih Doğruer. "The electronic, half-metallic, elastic, and magnetic properties of new PtWZ (Z = In, Tl, Sn, and Pb) half-Heusler alloys via GGA and GGA+mBJ methods." Physica Scripta 96, no. 12 (December 1, 2021): 125869. http://dx.doi.org/10.1088/1402-4896/ac3fcd.

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Abstract The first-principle calculations of PtWZ (Z = In, Tl, Sn, and Pb) half-Heusler alloys were calculated by WIEN2k for GGA and GGA+mBJ methods. First, the ferromagnetic (FM) phases were obtained more energetically stable than non-magnetic (NM) and antiferromagnetic (AFM) phases in each alloy. The Curie temperatures of PtWIn, PtWTl, PtWSn, and PtWPb alloys were obtained as 286.98 K, 467.14 K, 721.98 K, and 1114.31 K, respectively, by utilizing the energy differences of the AFM and FM phases. In each method and alloy used, spin-up electrons showed metallic character. In the GGA method, PtW(In, Tl) alloys have direct band gaps of 0.72044 eV and 0.91488 eV in spin-down electrons, while PtW(Sn, Pb) alloys have indirect band gaps of 1.2558 eV and 1.11892 eV, respectively. In the GGA+mBJ method, the bandgap directions in all compounds remained the same. Here, band gaps in PtW(In, Tl, Sn, and Pb) alloys were obtained as 0.99918 eV, 1.15385 eV, 1.42676 eV, and 1.17497 eV, respectively. While the total magnetic moment values of PtW(In, Tl) half-Heusler alloys were obtained as 1.00 μ B/f.u., the total magnetic moments of PtW(Sn, Pb) alloys were obtained as 2.00 μ B/f.u. These results are in full agreement with the Slater-Pauling rule. According to elastic calculations, PtWIn, PtWTl, PtWSn, and PtWPb half-Heusler alloys are elastically stable and ductile.

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Chen, Zixi, Yuya Sakuraba, Yoshio Miura, Zehao Li, Taisuke Sasaki, Hirofumi Suto, Varun K. Kushwaha, Tomoya Nakatani, Seiji Mitani, and Kazuhiro Hono. "Phase stability and half-metallic character of off-stoichiometric Co₂FeGa_0.5Ge_0.5 Heusler alloys." Journal of Applied Physics 132, no. 18 (November 14, 2022): 183902. http://dx.doi.org/10.1063/5.0109802.

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We investigate the effects of off-stoichiometric compositional variations from the Co2Fe(Ga0.5Ge0.5) (CFGG) full-Heusler alloy on its half-metallic electronic structure. First-principles calculations predict that the Co antisite defects that occupy Fe-sites (CoFe) lead to a finite DOS in the half-metallic gap of CFGG. Fe antisites defects in Co-sites (FeCo) introduced by excessing Fe composition, which could suppress the formation of CoFe, preserves the half-metallic gap but reduces spin polarization because the Fermi level shifts to the lower energy. We found that, in Fe-excess CFGG, Ge-excess has an important role to enhance the spin polarization by lifting up the Fermi level position and suppressing the formation of CoFe. To confirm the effect of the Fe and Ge-excess off-stoichiometric composition on spin polarization and phase-purity experimentally, we fabricated CFGG epitaxial thin films with various composition ratios (Co2− αFe1+ α) (Ga1− βGe β)1+ γ with small positive γ (=0.09–0.29). It turns out that Co1.75Ge or Fe1.7Ge secondary phase often forms in the films for [Formula: see text] in Fe-deficient [Formula: see text] and excess [Formula: see text] compositions. This secondary phase can be suppressed by tuning the Ge and Fe compositions, and the L21-phase pure film was found in Co39.4Fe29.3Ga13.4Ge17.9 [Formula: see text]. The measurements of conventional magnetoresistance effects qualitatively indicate higher spin polarization in the Co39.4Fe29.3Ga13.4Ge17.9 film compared to other Co-excess and Ge-deficient films, which evidences the benefit to make Fe- and Ge-excess off-stoichiometric CFGG for obtaining the half-metallic nature of CFGG.

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Wu, Zhigang, Yajiu Zhang, Zhuhong Liu, and Xingqiao Ma. "Influence of Symmetry from Crystal Structure and Chemical Environments of Magnetic Ions on the Fully Compensated Ferrimagnetism of Full Heusler Cr2YZ and Mn2YZ Alloys." Symmetry 14, no. 5 (May 12, 2022): 988. http://dx.doi.org/10.3390/sym14050988.

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Fully compensated ferrimagnets do not create any magnetic stray field and allow for a completely polarized current of charges. As a result, these alloys show promising prospects for applications as spintronic devices. In this paper, we investigated the phase stability, the site preference, the tetragonal distortion and the influence of symmetry from the crystal structure and chemical environments of magnetic ions on the magnetic properties of Cr2YZ and Mn2YZ (Y = void, Ni, Cu, and Zn; Z = Ga, Ge, and As) full Heusler alloys by first-principles calculations. We found that the selected Cr2-based alloys, except for Cr2NiGa and Cr2NiGe, prefer to crystallize in the centrosymmetric L21-type structure, while the selected Mn2-based alloys, except for Mn2CuAs, Mn2ZnGe and Mn2ZnAs, tend to crystallize in the non-centrosymmetric XA-type structure. Due to the symmetry, the antiferromagnetism of the selected L21-type alloys is very stable, and no spin-polarized density of states could be generated. In contrast, the magnetic moment of the selected XA-type alloys depends heavily on the number of valence electrons and tetragonal distortion, and spin-polarized density of states is generated. Therefore, the selected alloys with L21-type structures and their tetragonal-distorted structure are potential candidates for conventional antiferromagnets, while those with XA-type structure and their tetragonal-distorted structure are promising candidates for (fully) compensated ferrimagnets.

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Khmelevskyi, Sergii, Eszter Simon, László Szunyogh, and Peter Mohn. "Microscopic origin of ferro-antiferromagnetic transition upon non-magnetic substitution in Ru2(Mn1−xVx)Ge full Heusler alloys." Journal of Alloys and Compounds 692 (January 2017): 178–82. http://dx.doi.org/10.1016/j.jallcom.2016.09.017.

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Nazemi, N., and F. Ahmadian. "Half-metallic characteristic in the new full-Heusler SrYO-=SUB=-2-=/SUB=- (Y = Sc, Ti, V and Cr) -=SUP=-*-=/SUP=-." Физика твердого тела 61, no. 1 (2019): 41. http://dx.doi.org/10.21883/ftt.2019.01.47383.206.

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AbstractHalf-metallic properties of SrYO_2 (Y = Sc, Ti, V, and Cr) full-Hensler compounds were studied using full-potential linearized augmented plane wave method based on density functional theory. The negative formation energies of SrYO_2 (Y = Sc, Ti, V, and Cr) alloys confirmed that they can be synthesized experimentally. Total energy calculations showed that AlCu_2Mn-type structure was the ground state structure in all compounds. In both structures, SrYO_2 (Y = Ti, V, and Cr) alloys were half-metallic ferrromagnets, while SrScO_2 was a non- magnetic metal. The origin of half-metallicity was verified for SrCrO_2. SrYO_2 (Y = Ti, V, and Cr) alloys in both structures were half-metals in a wide range of lattice constants indicating that they are quite robust against hydrostatic strains. The magnetization of SrYO_2 (Y = Ti, V, and Cr) alloys was mainly originated from the 3 d electrons of Y (= Ti, V, and Cr) atoms and followed the Slater–Pauling rule: M _tot = Z _tot – 12. Generally, It is expected that SrYO_2 (Y = Ti, V, and Cr) alloys are promising and interesting candidates in the future spintronic field.

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Popoola, Adewumi I., and S. Babatunde Akinpelu. "Numerical Investigation of the Stability and Spintronic Properties of Selected Quaternary Alloys." European Journal of Applied Physics 3, no. 4 (July 8, 2021): 6–12. http://dx.doi.org/10.24018/ejphysics.2021.3.4.86.

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The use of electronic charge and spins (spintronics) has been proposed for much better data storage. This class of material is believed to have excellent capability for data integrity, low dynamic power consumption and high-density storage that showcases excellent protection against data loss. The spintronic and related properties have been investigated on four newly proposed quaternary alloys (NbRhGeCo, NbRhGeCr, NbRhGeFe and NbRhGeNi) through the first-principles calculation method of the Density Functional Theory (DFT). Specifically, the phonon frequencies, elastic stabilities, and the electronic structure were systematically studied in the full Heusler structure. The results predict that NbRhGeFe and NbRhGeCr are elastically and structurally stable. Both NbRhGeFe and NbRhGeCo are half-metals with ferromagnetic character, but NbRhGeCo is unfortunately elastically unstable. NbRhGeCr and NbRhGeNi are non-magnetic metallic alloys in their spin channels. All the results predict NbRhGeFe to be the only suitable among all the four alloys for spintronic application.

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10

Iftikhar, Aneeza, A. Afaq, Iftikhar Ahmad, Abu Bakar, H. Bushra Munir, Najm ul Aarifeen, and Muhammad Asif. "Computational Study of Ru2TiZ (Z = Si, Ge, Sn) for Structural, Mechanical and Vibrational Properties." Zeitschrift für Naturforschung A 74, no. 6 (June 26, 2019): 545–50. http://dx.doi.org/10.1515/zna-2019-0054.

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AbstractThe structural, mechanical and vibrational properties of Ru2TiZ (Z = Si, Ge, Sn) Full Heusler Alloys (FHAs) are computed using PBE-GGA as an exchange-correlation functional in Kohn–Sham equations. The calculated lattice constants of these alloys in L21 phase deviate from experimental values upto 0.85 % which shows a good agreement between the model and the experiments. These lattice constants are then used to compute the second order elastic constants C11, C12 and C44 with Wien2k-code. Elastic moduli and mechanical parameters are also calculated by these three independent elastic constants. Mechanical parameters Pugh’s and Poisson’s ratio indicate non-brittle nature of these alloys. Furthermore, the Debye temperature where the collective vibrations shift to an independent thermal vibration, longitudinal and transverse sound velocities, melting temperatures, and thermal conductivities are also obtained to investigate the phonon modes of oscillation. These phonon modes confirm the stability of these alloys as there exists no imaginary phonon frequency in the phonon-dispersion curves.

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Aarizou, Zineb, Soumia Bahlouli, and Mokhtar Elchikh. "Structural, electronic and magnetic properties of Ru2CrGe and Ru2MnGe: FP-LAPW calculations." Modern Physics Letters B 29, no. 18 (July 10, 2015): 1550093. http://dx.doi.org/10.1142/s0217984915500931.

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Structural and magnetic properties as well as the electronic structures of [Formula: see text] Heusler alloys were investigated in the framework of first principle calculation. Using the full-potential linearized augmented plane wave (FP-LAPW) in connection with the generalized gradient approximation (GGA) treatment of exchange-correlation energy, we have performed the structural optimization in the non-magnetic (NM) and three different magnetic configurations: FM, AFM-I and AFM-II. We have found that our two compounds are stable for the AFM-II state, which agree with the available experimental and theoretical results. The exchange constants [Formula: see text] and [Formula: see text] as well as the temperature of transition to the paramagnetic state [Formula: see text] were estimated here by the use of the energy difference method and the mean field approximation. The electronic structure of our compounds in their magnetic state was also studied. The GGA [Formula: see text]+ [Formula: see text]U method has also been used to take into account the strong correlations among the d orbitals of [Formula: see text] and [Formula: see text] atoms. This has considerably improved both the electronic and magnetic results which became close to the corresponding experimental data. We have finally studied the thermodynamic properties using the quasi-harmonic Debye model as implemented in the Gibbs Program.

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Yu, Zhi-Feng, Jun Lu, Hai-Long Wang, Xu-Peng Zhao, Da-Hai Wei, Jia-Lin Ma, Si-Wei Mao, and Jian-Hua Zhao. "Tunable Perpendicular Magnetic Anisotropy in Off-Stoichiometric Full-Heusler Alloy Co2MnAl." Chinese Physics Letters 36, no. 6 (May 2019): 067502. http://dx.doi.org/10.1088/0256-307x/36/6/067502.

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13

Volkova N. V., Chistyakov V. V., Patrakov E. I., Korenistov P. S., Perevalova A. N., and Emelyanova S. M. "Electrical resistance of Ni-=SUB=-42+x-=/SUB=-Mn-=SUB=-47-x-=/SUB=-Sn-=SUB=-11-=/SUB=- alloys." Physics of the Solid State 64, no. 3 (2022): 298. http://dx.doi.org/10.21883/pss.2022.03.53184.244.

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The electrical resistance and structure of Ni42+xMn47-xSn11 alloys have been studied; where x=0, 1, 2, 3, 4, At room temperature, Ni42+xMn47-xSn11 alloys are ordered in the cubic L21 Ni2MnSn structure characteristic of Heusler alloys. The phase transition between the cubic austenite phase and martensite with lower symmetry, characteristic of ferromagnetic non-stoichiometric Heusler alloys, is observed at temperatures below room temperature. It was found that the partial replacement of Mn atoms by Ni atoms leads to an increase in the phase transition temperatures and to their shift to room temperature. Keywords: Heusler alloys, electrical resistance, phase transition.

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Volkova N. V., Chistyakov V. V., Patrakov E. I., Korenistov P. S., Perevalova A. N., and Emelyanova S. M. "Electrical resistance of Ni-=SUB=-42+x-=/SUB=-Mn-=SUB=-47-x-=/SUB=-Sn-=SUB=-11-=/SUB=- alloys." Physics of the Solid State 64, no. 3 (2022): 310. http://dx.doi.org/10.21883/pss.2022.03.54698.244.

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The electrical resistance and structure of Ni42+xMn47-xSn11 alloys have been studied; where x=0, 1, 2, 3, 4, At room temperature, Ni42+xMn47-xSn11 alloys are ordered in the cubic L21 Ni2MnSn structure characteristic of Heusler alloys. The phase transition between the cubic austenite phase and martensite with lower symmetry, characteristic of ferromagnetic non-stoichiometric Heusler alloys, is observed at temperatures below room temperature. It was found that the partial replacement of Mn atoms by Ni atoms leads to an increase in the phase transition temperatures and to their shift to room temperature. Keywords: Heusler alloys, electrical resistance, phase transition.

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Singh, L. J., Z. H. Barber, Y. Miyoshi, W. R. Branford, and L. F. Cohen. "Structural and transport studies of stoichiometric and off-stoichiometric thin films of the full Heusler alloy Co2MnSi." Journal of Applied Physics 95, no. 11 (June 2004): 7231–33. http://dx.doi.org/10.1063/1.1667857.

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Sokolovskaya, Yulia, Olga Miroshkina, Danil Baigutlin, Vladimir Sokolovskiy, Mikhail Zagrebin, Vasilly Buchelnikov, and Alexey T. Zayak. "A Ternary Map of Ni–Mn–Ga Heusler Alloys from Ab Initio Calculations." Metals 11, no. 6 (June 17, 2021): 973. http://dx.doi.org/10.3390/met11060973.

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In the search for new magnetic functional materials, non-stoichiometric compounds remain a relatively unexplored territory. While experimentalists create new compositions looking for improved functional properties, their work is not guided by systematic theoretical predictions. Being designed for perfect periodic crystals, the majority of first-principles approaches struggle with the concept of a non-stoichiometric system. In this work, we attempt a systematic computational study of magnetic and structural properties of Ni–Mn–Ga, mapped onto ternary composition diagrams. Compositional stability was examined using the convex hull analysis. We show that the cubic austenite has its stability region close to the stoichiometric Ni2MnGa, in agreement with experimental data, while the tetragonal martensite spreads its stability over a wider range of Mn and Ni contents. The unstable compositions in both austenite and martensite states are located in the Ga-rich corner of the ternary diagram. We note that simultaneous stability of the austenite and martensite should be considered for potentially stable compounds suitable for synthesis. The majority of compounds are predicted to be ferrimagnetically ordered in both austenitic and martensitic states. The methodology used in this work is computationally tractable, yet it delivers some predictive power. For experimentalists who plan to synthesize stable Ni–Mn–Ga compounds with ferromagnetic order, we narrow the target compositional range substantially.

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Ari-Gur, Pnina, Giora Kimmel, James W. Richardson, Ashfia Huq, and Kapil Sharma. "Effect of Heat-Treatment on the Phases of Ni-Mn-Ga Magnetic Shape Memory Alloys." Solid State Phenomena 152-153 (April 2009): 497–500. http://dx.doi.org/10.4028/www.scientific.net/ssp.152-153.497.

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The Heusler alloys Ni50Mn25+xGa25-x display magnetic shape memory effect (MSM) with very fast and large reversible strain under magnetic fields. This large strain and the speed of reaction make MSM alloys attractive as smart materials. Our crystallographic investigation of these alloys, focused on non-stoichiometric composition with excess of manganese. Using neutron diffraction, we revealed the necessary processing parameters to achieve and preserve the homogeneous metastable one-phase martensitic structure that is needed for an MSM effect at room temperature.

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Zagrebin, Mikhail A., Vladimir V. Sokolovskiy, and Vasiliy D. Buchelnikov. "Ab Initio Study of Magnetic Properties and Phase Diagram of Ni-Mn-Ga Heusler Alloys." Materials Science Forum 738-739 (January 2013): 473–77. http://dx.doi.org/10.4028/www.scientific.net/msf.738-739.473.

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In this work the magnetic properties (exchange parameters, magnetic moment of non-stoichiometric Ni–Mn–Ga Heusler alloys with structural disorder by the help of ab initio calculations have been performed. Theoretical composition dependences of the total magnetic moment are in qualitative agreement in qualitative agreement with experimental data. Calculations of exchange parameters show that interactions between the Mn atoms in regular positions and Mn atoms in Ni and Ga positions are antiferromagnetic.

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Ari-Gur, Pnina, V. Ovidiu Garlea, Ashley Coke, Yan Ling Ge, Ilkka Aaltio, Simo Pekka Hannula, Hui Bo Cao, Amila S. B. Madiligama, and Victor V. Koledov. "Neutron Diffraction Study of a Non-Stoichiometric Ni-Mn-Ga MSM Alloy." Materials Science Forum 738-739 (January 2013): 103–7. http://dx.doi.org/10.4028/www.scientific.net/msf.738-739.103.

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Abstract. The structure and chemical order of a Heusler alloy of non-stoichiometric composition Ni-Mn-Ga were studied using constant-wavelength (1.538 Å) neutron diffraction at 363K and the diffraction pattern was refined using the FullProf software. At this temperature the structure is austenite (cubic) with Fm space group and lattice constant of a = 5.83913(4) [Å]. The chemical order is of critical importance in these alloys, as Mn becomes antiferromagnetic when the atoms are closer than the radius of the 3d shell. In the studied alloy the refinement of the site occupancy showed that the 4b (Ga site) contained as much as 22% Mn; that significantly alters the distances between the Mn atoms in the crystal and, as a result, also the exchange energy between some of the Mn atoms. Based on the refinement, the composition was determined to be Ni1.91Mn1.29Ga0.8

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Checca, N. R., R. J. Caraballo-Vivas, A. A. Coelho, A. Rossi, N. M. Fortunato, F. Mohseni, J. N. Gonçalves, J. S. Amaral, D. L. Rocco, and M. S. Reis. "Experimental realisation of off-stoichiometric Fe-Mn-Si full Heusler alloy with hexagonal crystal structure by pulsed laser deposition." Materials & Design 143 (April 2018): 268–73. http://dx.doi.org/10.1016/j.matdes.2018.01.062.

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Bera, Kousik, Supratik Mukherjee, M. Mukadam, Subrata Mondal, M. K. Firoz, G. Vaitheeswaran, Anushree Roy, and S. M. Yusuf. "Selective electronic excitations in nearly half-metallic Heusler alloy NiFeMnSn—A Raman spectroscopic study." Applied Physics Letters 121, no. 5 (August 1, 2022): 052404. http://dx.doi.org/10.1063/5.0097464.

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Half-metallic ferromagnetic full Heusler alloy NiFeMnSn is a promising material in spintronic device fabrication as it carries high spin polarization and high Curie temperature (Tc = 405 K). Understanding electronic excitations in a spin-polarized band structure is essential for the further use of this material in spin-based devices and to optimize the spin-dependent electronic structure in related compounds. In this Letter, we report electronic Raman scattering of NiFeMnSn with spectral signatures at a higher wavenumber than expected from the calculated phonon modes of the system. Temperature-dependent Raman spectroscopy demonstrates a non-monotonic behavior of the Raman shift with temperature across Tc. The orbital resolved electronic density of states and electronic band structure for both spin channels of the system, as obtained from the first principles density functional theory calculations, suggest that the observed Raman signatures originate from the Fe d orbital and its splitting due to the crystal field near the Fermi level. Furthermore, a strong magnetic field dependence of the spectral profile is observed. The study not only exhibits electronic Raman scattering in a Heusler alloy compound, which was unexplored to date, but also establishes Raman scattering as a promising probe to study the orbital-resolved partial density of states in the band structure near the Fermi level of a Heusler alloy.

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Chen, Ying, Bo Wu, and Hong Chen. "Effect of Nb Doping on Electronic and Magnetic Properties of Heusler Alloy Ti₂NiAl with Hg₂CuTi-Type Structure." Advanced Materials Research 535-537 (June 2012): 1295–98. http://dx.doi.org/10.4028/www.scientific.net/amr.535-537.1295.

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In this work, the electronic and magnetic properties of Nb-doped full-Huesler alloy Ti2NiAl with Hg2CuTi-type structure have been investigated by using first-principles calculations within the density function theory (DFT). Due to the Nb which has less valence electrons than Ni doping into Ni-site, the gap around the Fermi level of the compound Ti2Ni1-xNbxAl (0≤x≤1) is gradually narrowed, and destroyed completely as x≥0.5. With the increase of x, it has gone through the transition from the ferromagnetism to the non-magnetism, and then to the ferromagnetism finally. Further analyses of density of states reveal that the d-electronic rehybridization induced by Nb-doping and RKKY-type indirect interaction is directly responsible for the changes of half-metallicity and magnetism.

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Andrade, V. M., N. R. Checca, V. G. de Paula, K. R. Pirota, A. L. Rossi, F. Garcia, A. Vovk, S. A. Bunyaev, and G. N. Kakazei. "Full Heusler Fe2CrAl nanogranular films produced by pulsed laser deposition for magnonic applications." Journal of Applied Physics 134, no. 2 (July 12, 2023). http://dx.doi.org/10.1063/5.0151291.

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Obtaining Heusler alloys at the nanoscale with good crystallographic features is appealing for a large range of technological applications, from biomedical to spintronics devices. In particular, Fe2CrAl as bulk is known to present magnetic properties that are strongly sensitive to chemical and physical constraints, such as structural disorder and chemical composition. We report a throughout structural, morphological, and magnetic characterization of Fe2CrAl Heusler nanoparticles obtained by pulsed laser deposition technique. The nanoparticles are composed of slightly off-stoichiometric grains with two distinct morphologies where the role of chemical disorder and inhomogeneity on the magnetic behavior was evaluated. Through DC magnetization measurements, a superparamagnetic behavior is observed and a Gilbert damping of 9×10−3 is acquired from broadband ferromagnetic resonance data, which is comparable with standard materials used for magnonics applications. We discuss the complex magnetostructural coupling that rises on the nanoparticle system, comparing these results with the stoichiometric Fe2CrAl bulk target behavior.

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Idrissi, Samira, Soumia Ziti, Hicham Labrim, and Lahoucine Bahmad. "A Monte Carlo study of the yttrium-based Heusler alloys: Y2CrGa and YFeCrGa." Multidiscipline Modeling in Materials and Structures ahead-of-print, ahead-of-print (December 15, 2020). http://dx.doi.org/10.1108/mmms-09-2020-0221.

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PurposeIn this paper, using Monte Carlo simulations (MCSs) under the metropolis algorithm, the authors study the magnetic properties of the yttrium-based Heusler alloys: Y2CrGa and YFeCrGa. In the first step, the authors elaborate and discuss the ground-state phase diagrams of the more stable configurations. It is worth to note that the full-Heusler alloy Y2CrGa contains only one magnetic atom (Cr), while the quaternary Heusler alloy YFeCrGa has two magnetic atoms (Cr and Fe). This leads to modeling of the compound Y2CrGa by a Hamiltonian containing only one magnetic spin moment (S = 2), while the quaternary Heusler alloy YFeCrGa is modeled by a Hamiltonian containing two magnetic spin moments (Q = 5/2 and s = 2). The results of the study reveal that the critical temperature increases when increasing the reduced crystal field for the two studied compounds. To complete this study, the authors elaborated the hysteresis cycles of the two yttrium-based Heusler alloys: Y2CrGa and YFeCrGa.Design/methodology/approachIn this paper, the authors study the magnetic properties and the critical behavior of the yttrium-based Heusler alloys, Y2CrGa and YFeCrGa, using MCSs under the metropolis algorithm. In the first step, the authors elaborate and discuss the ground-state phase diagrams of the more stable configurations for the both structures at null temperature (T = 0). On the other hand, for non-null temperature (T ≠ 0), the authors investigate the critical behavior of these two yttrium-based Heusler alloys: Y2CrGa and YFeCrGa. It is worth to note that the full-Heusler alloy Y2CrGa contains only one magnetic atom (Cr), while the quaternary Heusler alloy YFeCrGa has two magnetic atoms (Cr and Fe). Hence, the compound Y2CrGa can be modeled by a Hamiltonian containing only one magnetic spin moment (S = 2), while the quaternary Heusler alloy YFeCrGa is modeled by a Hamiltonian containing two magnetic spin moments (Q = 5/2 and s = 2). Moreover, the results of the study reveal that the critical temperature increases when increasing the reduced crystal field for the two studied compounds. To complete this study, the authors elaborated the hysteresis cycles of the two yttrium-based Heusler alloys: Y2CrGa and YFeCrGa.FindingsThe authors elaborate the ground-state phase diagrams of the more stable configurations. It is worth to note that the full-Heusler alloy Y2CrGa contains only one magnetic atom (Cr), while the quaternary Heusler alloy YFeCrGa has two magnetic atoms (Cr and Fe). This leads to modeling of the compound Y2CrGa by a Hamiltonian containing only one magnetic spin moment (S = 2), while the quaternary Heusler alloy YFeCrGa is modeled by a Hamiltonian containing two magnetic spin moments (Q = 5/2 and s = 2). The results of the study reveal that the critical temperature increases when increasing the reduced crystal field for the two studied compounds. To complete this study, the authors elaborated the hysteresis cycles of the two yttrium-based Heusler alloys: Y2CrGa and YFeCrGa.Research limitations/implicationsThe authors elaborate the ground-state phase diagrams of the more stable configurations. It is worth to note that the full-Heusler alloy Y2CrGa contains only one magnetic atom (Cr), while the quaternary Heusler alloy YFeCrGa has two magnetic atoms (Cr and Fe). This leads to modeling of the compound Y2CrGa by a Hamiltonian containing only one magnetic spin moment (S = 2), while the quaternary Heusler alloy YFeCrGa is modeled by a Hamiltonian containing two magnetic spin moments (Q = 5/2 and s = 2). The results of the study reveal that the critical temperature increases when increasing the reduced crystal field for the two studied compounds. To complete this study, the authors elaborated the hysteresis cycles of the two yttrium-based Heusler alloys: Y2CrGa and YFeCrGa.Practical implicationsThe authors elaborate the ground-state phase diagrams of the more stable configurations. It is worth to note that the full-Heusler alloy Y2CrGa contains only one magnetic atom (Cr), while the quaternary Heusler alloy YFeCrGa has two magnetic atoms (Cr and Fe). This leads to modeling of the compound Y2CrGa by a Hamiltonian containing only one magnetic spin moment (S = 2), while the quaternary Heusler alloy YFeCrGa is modeled by a Hamiltonian containing two magnetic spin moments (Q = 5/2 and s = 2). The results of the study reveal that the critical temperature increases when increasing the reduced crystal field for the two studied compounds. To complete this study, the authors elaborated the hysteresis cycles of the two yttrium-based Heusler alloys: Y2CrGa and YFeCrGa.Social implicationsThe authors elaborate the ground-state phase diagrams of the more stable configurations. It is worth to note that the full-Heusler alloy Y2CrGa contains only one magnetic atom (Cr), while the quaternary Heusler alloy YFeCrGa has two magnetic atoms (Cr and Fe). This leads to modeling of the compound Y2CrGa by a Hamiltonian containing only one magnetic spin moment (S = 2), while the quaternary Heusler alloy YFeCrGa is modeled by a Hamiltonian containing two magnetic spin moments (Q = 5/2 and s = 2). The results of the study reveal that the critical temperature increases when increasing the reduced crystal field for the two studied compounds. To complete this study, the authors elaborated the hysteresis cycles of the two yttrium-based Heusler alloys: Y2CrGa and YFeCrGa.Originality/valueThe authors elaborate the ground-state phase diagrams of the more stable configurations. It is worth to note that the full-Heusler alloy Y2CrGa contains only one magnetic atom (Cr), while the quaternary Heusler alloy YFeCrGa has two magnetic atoms (Cr and Fe). This leads to modeling of the compound Y2CrGa by a Hamiltonian containing only one magnetic spin moment (S = 2), while the quaternary Heusler alloy YFeCrGa is modeled by a Hamiltonian containing two magnetic spin moments (Q = 5/2 and s = 2). The results of the study reveal that the critical temperature increases when increasing the reduced crystal field for the two studied compounds. To complete this study, the authors elaborated the hysteresis cycles of the two yttrium-based Heusler alloys: Y2CrGa and YFeCrGa.

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25

Aladerah, Bilal, Maen F. Gharaibeh, Abdalla Obeidat, and Khaled Aledealat. "A comparative study of structural, electronic, magnetic, and pressure-dependent properties of Full-Heusler Fe2XSi (X=Mn and Co): First-principles calculation and Monte Carlo Simulation." Physica Scripta, July 19, 2023. http://dx.doi.org/10.1088/1402-4896/ace8ce.

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Abstract This study investigates the structural, electronic, magnetic, and pressure-dependent properties of Fe2XSi (X=Mn and Co) full-Heusler alloy through a comprehensive computational approach. The structural stability of these alloys confirmed L21 and XA prototypes as favorable structures for Fe2MnSi and Fe2CoSi, respectively. In addition, Fe2MnSi exhibits 100% spin polarization suggesting its potential suitability for spintronics applications. Conversely, Fe2CoSi does not exhibit similar behavior. The calculated magnetic moments of these alloys revealed an increase due to Coulomb interaction (U). The magnetic moments satisfy the Slater-Pauling relation, with calculated values of 3 μ_B for Fe2MnSi and 5 μ_B for Fe2CoSi. Heisenberg exchange interaction parameters are calculated to illustrate distinct magnetic interactions within the alloys. The study further explores thermomagnetic properties through Monte Carlo simulations, including thermal magnetization, thermal magnetic susceptibility, and Curie temperature (T_C). The calculated T_C were found to be 294K for Fe2MnSi and 1029K for Fe2CoSi, showing close agreement with experimental data. We additionally investigate the pressure-dependent properties of these alloys, revealing a non-linear dependence of the band gap on pressure for Fe2MnSi, with values decreasing from 0.668 eV to 0.259 eV as pressure increased from -15.917 to 23.712 GPa. For Fe2CoSi, the band gap remained zero across varying pressure conditions, indicating its metallic conducting behavior.

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26

Pal, Soumyadipta, and Subarna Datta. "Study of structural, magnetic and electronic properties of a new off-stoichiometric series of full-Heusler alloy Co2Nb1+Z1− (Z = Sn, In, Ga): Ab initio approach." Journal of Alloys and Compounds, April 2023, 170117. http://dx.doi.org/10.1016/j.jallcom.2023.170117.

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27

Gheriballah, Slimane, A. Chahed, Y. Benazzouzi, and H. Rozale. "Structural, mechanical, electronic, and thermoelectric properties of new semiconducting d0 quaternary Heusler compounds CaKNaZ (Z =Si, Ge, Sn). A density functional theory study." Revista Mexicana de Física 68, no. 5 Sep-Oct (August 16, 2022). http://dx.doi.org/10.31349/revmexfis.68.050501.

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Due to the increasing demand for energy, the development of new and good thermoelectric (TE) materials is very vital. In this study, with ab initio calculations, based on the density functional theory (DFT) using the self-consistent full potential linearized augmented plane wave (FPLAPW) method were performed to explore the structural, mechanical, electronic and thermoelectric properties of quaternary alloys CaKNaZ (Z = Si, Ge, Sn) with quaternary Heusler structure. optimization confirmed the most stable structure for CaKNaZ (Z = Si, Ge, Sn) compounds is Y1-type in the non-magnetic phase. All of the compounds have been shown to behave like semiconductors, with indirect band gaps of 0.82 and 0.69 for CaKNaSi, CaKNaSn respectively, and direct band gap of 0.46 for CaKNaGe. The theoretical study of thermoelectric properties for CaKNaZ (Z = Si, Ge, Sn) was carried out by Boltzmann theory as implemented in BoltzTraP code. we have obtained a high of figure of merit at moderate temperatures. This indicates that the studied alloys can be used in thermoelectric applications.

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Bouadi, Abed, Tayeb Lantri, Smain Mesbah, Mohammed Houari, I. Ameri, Lamia Blaha, Mohammed Ameri, Y. Al-Douri, and A. F. Abd El-Rehim. "A new semiconducting full Heusler Li₂BeX (X = Si, Ge and Sn): first-principles phonon and Boltzmann calculations." Physica Scripta, September 15, 2022. http://dx.doi.org/10.1088/1402-4896/ac925f.

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Abstract The Full Potential-Linearized Augmented Plane Wave (FP-LAPW) is employed into density functional theory (DFT) within WIEN2k package to explore and investigate the thermoelectric, mechanical, electronic and structural properties of full-Heusler alloys Li2BeX (X= Si, Ge and Sn) were explored. The exchange and correlation potential are treated by different approximations: the generalized gradient approximation with Perdew–Burke–Ernzerhof scheme (GGA-PBE) and Tran–Blaha modified Becke–Johnson (mBJ-GGA). The results achieved for the electronic prop-erties show that these compounds are semiconductor in nature with an indirect band gap, of val-ues: 0.60 eV, 0.55 eV and 0.24 eV for Li2BeSi, Li2BeGe and Li2BeSn, respectively. In addition, these materials are mechanically stable owing to the fact that the conditions required for this me-chanical stability satisfy Born's criteria, and are of a brittle nature due to the calculated values of the ratios (B/G), on the other hand, these compounds are dynamically stable due to the non-presence of negative frequencies following the detailed study of phonons. These compounds are characterized by a high figure of merit (ZT) (close to unity) and high Seebeck coefficient (S), making them promising candidates for thermoelectric applications.

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Chumak, O. M., A. Pacewicz, A. Lynnyk, B. Salski, T. Yamamoto, T. Seki, J. Z. Domagala, et al. "Magnetoelastic interactions and magnetic damping in Co2Fe0.4Mn0.6Si and Co2FeGa0.5Ge0.5 Heusler alloys thin films for spintronic applications." Scientific Reports 11, no. 1 (April 7, 2021). http://dx.doi.org/10.1038/s41598-021-87205-y.

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AbstractCo2Fe0.4Mn0.6Si (CFMS) and Co2FeGa0.5Ge0.5 (CFGG) Heusler alloys are among the most promising thin film materials for spintronic devices due to a high spin polarization, low magnetic damping and giant/tunneling magnetoresistance ratios. Despite numerous investigations of Heusler alloys magnetic properties performed up to now, magnetoelastic effects in these materials remain not fully understood; due to quite rare studies of correlations between magnetoelastic and other magnetic properties, such as magnetic dissipation or magnetic anisotropy. In this research we have investigated epitaxial CFMS and CFGG Heusler alloys thin films of thickness in the range of 15–50 nm. We have determined the magnetoelastic tensor components and magnetic damping parameters as a function of the magnetic layer thickness. Magnetic damping measurements revealed the existence of non-Gilbert dissipation related contributions, including two-magnon scattering and spin pumping phenomena. Magnetoelastic constant B11 values and the effective magnetic damping parameter αeff values were found to be in the range of − 6 to 30 × 106 erg/cm3 and between 1 and 12 × 10–3, respectively. The values of saturation magnetostriction λS for CFMS Heusler alloy thin films were also obtained using the strain modulated ferromagnetic resonance technique. The correlation between αeff and B11, depending on magnetic layer thickness was determined based on the performed investigations of the above mentioned magnetic properties.

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Khovailo, Aleksandr, Aidar Murtazin, Evgeniy Kolesnikov, Efim Argunov, Dmitry Karpenkov, Aleksandr Shubin, Irina Bazhenova, Aleksandra Khvan, Aleksei Bogach, and E. M. Elsehly. "Structural properties of non-stoichiometric Fe–Ti–Sn and Fe–V–Al Heusler alloys." MRS Advances, April 11, 2023. http://dx.doi.org/10.1557/s43580-023-00564-8.

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31

Yadav, Kavita, and Kaustav Mukherjee. "Evidence of multi-band superconductivity in non-centrosymmetric Full Heusler alloy LuPd2Sn." Journal of Physics: Condensed Matter, March 30, 2023. http://dx.doi.org/10.1088/1361-648x/acc919.

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Abstract In this work, evidence of multi-band superconductivity and presence of mixed parity states in full Heusler alloy (FHA) LuPd2Sn is investigated using the X-ray diffraction, temperature and field dependent resistivity, temperature dependent magnetization, and heat capacity measurements. Our studies reveal that LuPd2Sn is a type II superconductor and undergoes superconducting transition below 2.5 K. Above 2.5 K, the temperature and field dependence of resistivity indicate to the presence of multiple bands and inter-band phonon assisted scattering. The upper critical field, HC2 (T) exhibits linear behaviour and deviates from Werthamer, Helfand and Hohenberg model over the measured temperature range. Additionally, the Kadowaki-Woods ratio plot supports the unconventional superconductivity in this alloy. Moreover, a significant deviation from the s-wave behaviour is noted, which is studied using phases fluctuation analysis. It indicates the presence of spin triplet along with spin singlet component arising due to antisymmetric spin orbit coupling.

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32

Bersweiler, Mathias, Philipp Bender, Inma Peral, Evelyn Pratami Sinaga, Dirk Honecker, Diego Alba Venero, Ivan Titov, and Andreas Michels. "Magnetic nanoprecipitates and interfacial spin disorder in zero-field-annealed Ni₅₀Mn₄₅In₅ Heusler alloys as seen by magnetic small-angle neutron scattering." Journal of Applied Crystallography 55, no. 4 (July 15, 2022). http://dx.doi.org/10.1107/s1600576722006355.

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Shell ferromagnetism is a new functional property of certain off-stoichiometric Ni–Mn–In Heusler alloys, with a potential application in non-volatile magnetic memories and recording media. One key challenge in this field remains the determination of the structural and magnetic properties of the nanoprecipitates that are the result of an annealing-induced segregation process. Thanks to its unique mesoscopic length scale sensitivity, magnetic small-angle neutron scattering appears to be a powerful technique to disclose the microstructure of such annealing-induced nanoprecipitates. In this study, the microstructure of a zero-field-annealed off-stoichiometric Ni50Mn45In5 Heusler alloy is investigated by unpolarized magnetic small-angle neutron scattering. The neutron data analysis reveals a significant spin-misalignment scattering, which is mainly related to the formation of annealing-induced ferromagnetic nanoprecipitates in an antiferromagnetic matrix. These particles represent a source of perturbation which, due to dipolar stray fields, gives rise to canted spin moments in the surroundings of the particle–matrix interface. The presence of anticorrelations in the computed magnetic correlation function reflects the spatial perturbation of the magnetization vector around the nanoprecipitates. The magnetic field dependence of the zero crossing and the minima of the magnetic correlation function are qualitatively explained using the law of approach to ferromagnetic saturation for inhomogeneous spin states. More specifically, at remanence, the nanoprecipitates act magnetically as one superdefect with a correlation length that lies outside the experimental q range, whereas near saturation the magnetization distribution follows each individual nanoprecipitate. Analysis of the neutron data yields an estimated size of 30 nm for the spin-canted region and a value of about 75 nm for the magnetic core of the individual nanoprecipitates.

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Liu Rong-tao, Wang Chen-yang, Huang Jia-mian, Luo Peng-fei, Liu Xin, Ye Song, Dong Zi-rui, Zhang Ji-ye, and Luo Jun. "Preparation and thermoelectric properties of Sc-doped Ti1-xNiSb half-Heusler alloys." Acta Physica Sinica, 2023, 0. http://dx.doi.org/10.7498/aps.72.20230035.

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The nominal composition TiNiSb with 19 valence electrons is demonstrated to be composed of off-stoichiometric half-Heusler phase and impurities. In this work, the Ti1-xNiSb (x=0, 0.10, 0.15, 0.20, 0.25) samples were first prepared by ball milling and spark plasma sintering. The single-phase Ti0.9NiSb sample, deviating from the theoretical composition Ti0.75NiSb base on 18-electron rule, is obtained, which might be ascribed to the small defect formation energy of Ti filling the vacancy as well as our ball-milling preparation method. With the single-phase Ti0.9NiSb sample as the base material, a small amount of Sc is used to partially replace Ti in order to further reduce the carrier concentration. Thus, the Ti1-x-yScyNiSb (x=0.10,0.15;y=0.03,0.05) samples are designed to investigate the effect of Sc doping on the thermoelectric properties. X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) analysis confirms the single-phase nature of the Ti1-x-yScyNiSb samples. Energy-dispersive X-ray spectroscopy (EDS) results indicate that the actual compositions of the Ti1-x-yScyNiSb samples agree well with their nominal compositions, and all the elements distribute uniformly in the sample. Moreover, the doping of Sc can increase the content of Ti vacancy while maintaining the single-phase structure, which could be attributed to the higher binding energy between Sc and Sb because the electronegativity of Sc is less than that of Ti. Both the substitution of Sc for Ti and the increase of the Ti vacancies significantly reduce the carrier concentration, which decreases from~13.6 × 1021 cm-3 for Ti0.9NiSb to~3.4 × 1021 cm-3 for Ti0.8Sc0.05NiSb. The decreased carrier concentration results in greatly increased Seebeck coefficient, and thus the Ti0.8Sc0.05NiSb sample achieve a power factor as high as 17.7 μW/(cm·K2) at 973 K. Although the lattice thermal conductivity of Sc-doped samples increases slightly owing to the reduction of electron-phonon scattering and the enhancement of chemical bonds, the total thermal conductivity decreases dramatically due to the greatly reduced electronic thermal conductivity. Finally, the Ti0.8Sc0.05NiSb sample reaches a zT value of~0.42 at 973K, which is 180% higher than that of Ti0.9NiSb sample. Despite that the thermoelectric performance of our sample is still inferior to those of the state-of-the-art off-stoichiometric 19-electron half-Heusler alloys, this work demonstrates that the thermoelectric performance of Ti1-xNiSb can be further improved by non-isoelectronic doping.

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34

Chaudhuri, S., D. Salas, V. Srihari, E. Welter, I. Karaman, and P. A. Bhobe. "Half metallicity in Cr substituted Fe2TiSn." Scientific Reports 11, no. 1 (January 12, 2021). http://dx.doi.org/10.1038/s41598-020-79895-7.

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AbstractBand structure tailoring has been a great avenue to achieve the half-metallic electronic ground state in materials. Applying this approach to the full Heusler alloy Fe2TiSn, Cr is introduced systematically at Ti site that conforms to the chemical formula $${\text{Fe}}_{2} {\text{Ti}}_{{1 - x}} {\text{Cr}}_{x}$$ Fe 2 Ti 1 - x Cr x Sn. Compositions so obtained have been investigated for its electronic, magnetic, and electrical transport properties with an aim to observe the half-metallic ferromagnetic ground state, anticipated theoretically for Fe2CrSn. Our experimental study using synchrotron X-ray diffraction reveals that only compositions with $$x \le$$ x ≤ 0.25 yield phase pure L2$$_1$$ 1 cubic structures. The non-magnetic ground state of Fe2TiSn gets dramatically affected upon inclusion of Cr giving rise to a localized magnetic moment in the background of Ruderman–Kittel–Kasuya–Yosida (RKKY) correlations. The ferromagnetic interactions begin to dominate for x = 0.25 composition. Results of its resistivity and magnetoresistance (MR) measurement point towards a half-metallic ground state. The calculation of exchange coupling parameter, $$\hbox {J}_{{ij}}$$ J ij , and orbital projected density of states that indicate a change in hybridization between 3d and 5p orbital, support the observations made from the study of local crystal structure made using the extended X-ray absorption fine structure spectroscopy. Our findings here highlight an interesting prospect of finding half-metallicity via band structure tailoring for wide application in spintronics devices.

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Talantsev, Evgeny F. "Electron-phonon coupling constant and BCS ratios in the LaH10-y doped with magnetic rare earth element." Superconductor Science and Technology, June 30, 2022. http://dx.doi.org/10.1088/1361-6668/ac7d78.

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Abstract Stoichiometric near-room temperature superconductors (NRTS) (for instance, H3S and LaH10) exhibit a high ground state upper critical field, B c2(0) > 100 T, such that the magnetic phase diagram in these materials cannot be measured in non-destructive experiments. However, Semenok et al. (2022 arXiv2203.06500) proposed the idea of exploring the full magnetic phase diagram in NRTS samples, in which superconducting order parameter is suppressed by magnetic element doping. If the element is uniformly distributed in the material, then the theory of electron-phonon mediated superconductivity predicts the suppression of the order parameter in a three-dimensional s-wave superconductor. Semenok et al. (arXiv2203.06500) experimentally proved this idea for LaH10 by substituting lanthanum with the magnetic rare earth neodymium. As a result, the transition temperature in La1-xNdxH10 (x = 0.09) was suppressed to T c ~ 120 K, and the upper critical field decreases to B c2(T=41 K) = 55 T. While the exact hydrogen content should be further established in the (La1-xNdx)H10-y (x = 0.09) (because similar T c suppression was observed in hydrogen deficient LaH10-y samples reported by Drozdov et al (2019 Nature 569 528)), a significant part of the full magnetic phase diagram for (La1-xNdx)H10-y (x = 0.09) sample was measured. Here we analyzed the reported (Semenok et al (2022 arXiv2203.06500)) magnetoresistance data for La1-xNdxH10 (x=0.09) compressed at P = 180 GPa and deduced: (a) Debye temperature, Tθ = 1156 ± 6 K, (b) the electron-phonon coupling constant, λe-ph = 1.65 ± 0.01; (c) the ground state superconducting energy gap, Δ(0) = 20.2 ± 1.3 meV; (d) the gap-to-transition temperature ratio, 2Δ(0)/kBTc = 4.0 ± 0.2; and (e) the relative jump in specific heat at transition temperature, ΔC/γT c = 1.68 ± 0.15. The deduced values indicate that La1-xNdxH10 (x = 0.09; P = 180 GPa) is a moderately strongly coupled s-wave superconductor.

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Journal articles on the topic 'Non-stoichiometric Full Heusler Alloys'

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