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Artículos de revistas sobre el tema "Double Perovskite Manganites"

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Publicado: 6 de septiembre de 2023

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1

GU, R. Y. y Z. D. WANG. "SPIN AND ORBITAL PHYSICS IN MANGANITES". International Journal of Modern Physics B 15, n.º 19n20 (10 de agosto de 2001): 2727–45. http://dx.doi.org/10.1142/s0217979201006501.

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The spin and orbital physics in perovskite manganites is briefly reviewed. Perovskite manganites are well known as the materials exhibiting colossal magnetoresistance (CMR), whose mechanism is based on the double exchange (DE) interaction, in which the electron hopping is connected with the spin configurations of the manganite ions. Recent intensive studies have shown that this DE framework must be subjected to the strong correlation between orbital degenerate electrons. On one hand, the orbital degeneracy itself leads to an anisotropic DE hopping being different from the conventional DE, which in turn may result in the anisotropy of the magnetic structure, such as the A-type or the C-type antiferromagnetism. On the other hand, the electronic correlation between these degenerate electrons plays an important role in determining the phases of the system. The correlation can come from both the on-site Coulomb interaction and the Jahn–Teller coupling between the lattice distortion and the electrons. The interplay of the DE mechanism and the strong electronic correlation leads to various magnetic, orbital and/or charge ordering as well as the phase separation.
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2

Zhou, J. S. y J. B. Goodenough. "Phonon-Assisted Double Exchange in Perovskite Manganites". Physical Review Letters 80, n.º 12 (23 de marzo de 1998): 2665–68. http://dx.doi.org/10.1103/physrevlett.80.2665.

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3

Solana-Madruga, Elena, Clemens Ritter, Olivier Mentré, J. Paul Attfield y Ángel M. Arévalo-López. "Giant coercivity and spin clusters in high pressure polymorphs of Mn2LiReO6." Journal of Materials Chemistry C 10, n.º 11 (2022): 4336–41. http://dx.doi.org/10.1039/d2tc00451h.

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New high-pressure ordered-ilmenite and double-perovskite polymorphs of Mn2LiReO6 are unprecedented A-site manganites with B/B′ +/7+ oxidation states. They show cluster spin-cluster-glass behaviour and giant coercivity without spin–orbit-coupling.
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4

Bao, Wei, J. D. Axe, C. H. Chen, S. W. Cheong, P. Schiffer y M. Roy. "From double exchange to superexchange in charge-ordering perovskite manganites". Physica B: Condensed Matter 241-243 (diciembre de 1997): 418–20. http://dx.doi.org/10.1016/s0921-4526(97)00607-8.

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5

Wang, Zhiming, Qingyu Xu, Gang Ni y He Zhang. "Magnetic entropy change in perovskite manganites La0.6Pr0.1Pb0.3MnO3 with double metal–insulator peaks". Physica B: Condensed Matter 406, n.º 23 (diciembre de 2011): 4333–37. http://dx.doi.org/10.1016/j.physb.2011.08.015.

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6

Craus, M. L., N. Cornei y T. L. To. "Low-Doped La0.54Ho0.11Sr0.35Mn1-XVxO3 Manganites: Vanadium Influence on Transport Phenomena and Magnetic Properties". Solid State Phenomena 190 (junio de 2012): 85–88. http://dx.doi.org/10.4028/www.scientific.net/ssp.190.85.

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Transport phenomena in manganites (ABO3), and indirectly the transition temperature from metallic to insulator state (TMI), can be controlled by hole doping and the average ionic size at A positions (). In agreement with Zener theory, the strength of double exchange is determined by the Mn-O length (dMnO) and Mn-O-Mn angles () of the Mn-O-Mn bonds. We will investigate the influence of substitution of Mn with V on the crystalline structure and transport characteristics in La0.54Ho0.11Sr0.35Mn1-xVxO3 manganites. The samples were prepared by sol-gel method to improve the purity and homogeneity of the samples. By XRD it was established that the samples contain only ABO3 perovskite phases, except the samples with x0.1. The resistance of the samples vs temperature was determined by four probes method. The specific magnetization was obtained by using a Foner type magnetometer, working at 1.4 T, between 77 and 400 K.
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7

Dudric, Roxana, Gabriela Souca y Firuța Goga. "Magnetocaloric Effect in LA1.2R0.2CA1.6MN2O7 (R=Tb, Dy, Ho, Er) Perovskites Synthesized by Sol-Gel Method". Studia Universitatis Babeș-Bolyai Physica 67, n.º 1-2 (30 de diciembre de 2022): 9–16. http://dx.doi.org/10.24193/subbphys.2022.01.

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"Nanocrystalline double layered La1.2R0.2Ca1.6Mn2O7 manganites with R = Tb, Dy, Ho, and Er were synthesized by sol-gel method. The XRD measurements indicate that all samples are single phase with a Sr3Ti2O7-type tetragonal (I4/mmm) structure and mean crystallite sizes between 22 nm and 27 nm. The magnetic measurements evidence a spin-glass like behavior at low temperatures for all samples, which may be due to frustration of random competing ferromagnetic and antiferromagnetic interactions together with the anisotropy originating from the layered structure. A moderate magnetocaloric effect was found for all samples, with the maximum entropy change located at temperatures near the magnetic transition ones, but high RCP(S) values were obtained due to the broadened magnetic entropy curves. Keywords: nanoparticles, double layered perovskite, magnetocaloric effect. "
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8

VARSHNEY, DINESH y N. KAURAV. "LOW TEMPERATURE SPECIFIC HEAT ANALYSIS OF LaMnO3+δ MANGANITES". International Journal of Modern Physics B 20, n.º 28 (10 de noviembre de 2006): 4785–97. http://dx.doi.org/10.1142/s021797920603559x.

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We report a theoretical analysis for the experimental specific heat C(T) data of the perovskite manganites LaMnO 3+δ, with δ=0.11, 0.15 and 0.26, in the temperature domain 4≤T≤10 K . Calculations of C(T) have been made within the two-component scheme: one is the Fermionic and the other is Bosonic (phonon or magnon) contribution. Lattice specific heat is well estimated from the Debye temperature for lanthanum manganites with different δ obtained following an overlap repulsive potential. Fermionic component as the electronic specific heat coefficient is deduced using the band structure calculations. Later on, following double exchange mechanism the role of magnons is assessed toward specific heat and is found that at low temperatures, specific heat shows almost T3/2 dependence on the temperature. We note that the lattice specific heat is smaller for δ=0.11 when compared with that of magnon specific heat below 6 K, while the lattice contribution is larger with the magnon contribution for δ=0.15 and 0.26. It is further noticed that in the ferromagnetic phase, deduced electronic specific heat is smaller in comparison with reported large electronic term in low temperature domain. The present investigations allow us to stress that electron correlations are essential to enhanced density of state over simple Fermi liquid approximation in pure LaMnO 3+δ (δ=0.11, 0.15 and 0.26). These findings express that the large Coulomb interaction U suppresses the double occupancies of eg electrons and enhanced electronic specific heat, while there is a decrease of T3/2-term with δ from 0.26 to 0.11. The present numerical analysis of specific heat shows similar results as those revealed from experiments.
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9

Lu, Chengliang, Menghao Wu, Lin Lin y Jun-Ming Liu. "Single-phase multiferroics: new materials, phenomena, and physics". National Science Review 6, n.º 4 (1 de julio de 2019): 653–68. http://dx.doi.org/10.1093/nsr/nwz091.

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Abstract Multiferroics, where multiple ferroic orders coexist and are intimately coupled, promise novel applications in conceptually new devices on one hand, and on the other hand provide fascinating physics that is distinctly different from the physics of high-TC superconductors and colossal magnetoresistance manganites. In this mini-review, we highlight the recent progress of single-phase multiferroics in the exploration of new materials, efficient roadmaps for functionality enhancement, new phenomena beyond magnetoelectric coupling, and underlying novel physics. In the meantime, a slightly more detailed description is given of several multiferroics with ferrimagnetic orders and double-layered perovskite structure and also of recently emerging 2D multiferroics. Some emergent phenomena such as topological vortex domain structure, non-reciprocal response, and hybrid mechanisms for multiferroicity engineering and magnetoelectric coupling in various types of multiferroics will be briefly reviewed.
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10

Tovstolytkin, A. I., A. N. Pogorilyi y S. M. Kovtun. "Double-peaked character of the temperature dependence of resistance of perovskite manganites for a broadened ferromagnetic transition". Low Temperature Physics 25, n.º 12 (diciembre de 1999): 962–65. http://dx.doi.org/10.1063/1.593848.

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11

Ji, Denghui, Bin Zhang, Yong Yang, Shuling Wang, Yingdi Liu, Yuanping Shi, Shunzhen Feng, Cuijian Zhao, Shaohui Shi y Qingqing Zhang. "The structural, magnetic and electrical transport properties of perovskite La0.67Sr0.33Mn1−x(VMn)xO3: The B-sites vacancies as a rapier". Modern Physics Letters B 35, n.º 25 (5 de agosto de 2021): 2150415. http://dx.doi.org/10.1142/s0217984921504157.

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The polycrystalline samples of manganites perovskite [Formula: see text] with B-sites vacancies were synthesized using the conventional solid-state reaction method. The results based on the X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) analyses show that the samples with [Formula: see text] have a secondary phase of lanthanum oxides. It indicates there is a maximum vacancy content at the B-sites with [Formula: see text]. By X-ray Photoelectron Spectra (XPS), the ionicities of oxygen were determined to be 0.762, 0.842, and 0.886, corresponding to [Formula: see text], 0.03, and 0.05, respectively. The B-sites vacancy plays an important role in magnetic performances: (i) B-sites vacancy changes the contents and the average cant angle of Mn cations, and makes the specific saturation magnetization at 100 K and 300 K increase, and then decrease rapidly. (ii) The Curie temperature changes in a small range from 363.93 K to 366.00 K, resulting from both the double exchange interaction increasing and the double exchange path destroyed by the vacancies. (iii) The magnetoresistance (MR) at room temperature achieves 6.97% in the [Formula: see text] sample, whose value is larger than that of [Formula: see text] sample.
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12

Krishnan, Kannan M., Honglyoul Ju y C. Nelson. "Electronic Structure and Conductivity Mechanism in Manganite Thin Films Exhibiting Colossal Magnetoresistance". Microscopy and Microanalysis 4, S2 (julio de 1998): 620–21. http://dx.doi.org/10.1017/s1431927600023229.

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Perovskite manganites, which have the the general formula R1-xAxMnO3 (R = La, Pr, or Nd and A = Ca, Sr, Ba, or Pb), have generated much recent interest because they exhibit “colossal magnetoresistance” (CMR), i.e. a small change in an applied magnetic field dramatically changes the electrical resistance of the material. Materials that exhibit this effect are being developed for various field-sensing applications but currently, the mechanism by which CMR occurs is not known. Conduction in these materials is explained by the “double exchange” mechanism, where the conductivity is attributed to electrons hopping back and forth between neighboring manganes ions. Such hopping is a maximum when the magnetic moments of the magnese ions are aligned parallel and a minimum when they are aligned antiparallel. In short, these materials show metallic conductivity when they are ferromagnetic and insulating behavior when they are antiferromagnetic. Moreover, they change from metallic to insulating behavior as a function of temperature.
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13

Rahman, Ikhwan Nur, Budhy Kurniawan, Dhawud Sabilur Razaq, Arief Sudarmaji y Dicky Rezky Munazat. "Structural and Morphological La0.85-xBaxNa0.15MnO3 (x = 0, 0.05, 0.10 and 0.15) Perovskite Manganite". Key Engineering Materials 860 (agosto de 2020): 95–100. http://dx.doi.org/10.4028/www.scientific.net/kem.860.95.

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Bulk polycrystalline samples La0.85-xBaxNa0.15MnO3 (x = 0, 0.05, 0.10 and 0.15) manganites were synthesized by the sol-gel route. The effect of Barium (Ba) existence on the structural and morphological was investigated by X-ray diffraction (XRD) and Scanning Electron Microscope (SEM). The structural parameters were obtained using Rietveld refinement of the XRD pattern. It was revealed the structures of compounds have rhombohedral with R-3c space group without any impurities phase. Furthermore, several changes are found to exist due to Ba substitution such as the lattice parameter, unit cells volume, average crystallite size, average Mn-O bond length (<Mn – O>) and average Mn-O-Mn bond angle (<Mn – O – Mn>). The changes in <Mn – O> and <Mn – O – Mn> due to Ba substitution, affects the double exchange interaction of the samples. SEM images reveal the existence of Ba also affects the morphology of the studied samples, which consisted of polygonal grains with homogeneous chemical composition.
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14

Chin, Hui Wei, Kean Pah Lim, S. A. Halim, S. K. Chen, S. W. Ng, Albert H. M. Gan y K. H. Cheong. "Influence of Grain Formation on Electrical Properties of La0.67Sr0.33MnO3". Advanced Materials Research 1107 (junio de 2015): 255–60. http://dx.doi.org/10.4028/www.scientific.net/amr.1107.255.

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In this work, polycrystalline perovskite manganites of La0.67Sr0.33MnO3 (LSMO) sample was prepared by two wet chemical methods: co-precipitation (CP) and sol-gel (SG) methods. Both samples were sintered at high temperature (1300 °C) for longer duration (24 hours) to investigate the effect of grains formation on its electrical properties. XRD results show that both samples were forming single LSMO phase with hexagonal structure (R-3c). SG sample shows smaller grain size (~220nm) however the CP sample (~4.45μm) was about 20-fold larger. Slower grain growth takes place in SG sample due to the triple junction effect where grain growth in nanocrystal is limited. Terrace patterns are noticed on the surface of CP sample which is suspected as the occurrence full crystallization or recrystallisation. TP of SG sample was shifted to lower temperature (298 K) due to the significant magnetically disordered layer across the grain boundaries which had weakened double exchange effect. SG sample displays higher extrinsic MR (-10.8%, 1 kG) and intrinsic MR (-25.1%, 10 kG) at 80 K due to the Core-Shell effect in the nanograin. However, grain boundaries (shell) effect is weakening in full crystallite CP sample. Hence, only intrinsic MR can be observed which is-15.6% at 10 kG applied field. Consequently, extrinsic MR is dominant in sol-gel sample however intrinsic MR is dominant in co-precipitation sample. Therefore, the grain size and microstructure formation affect the Tp, resistivity and magnetoresistive effect.
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15

Handayani, Ismudiati Puri, N. Mufti, Agustinus Agung Nugroho, T. T. M. Palstra y P. H. M. van Loosdrecht. "Raman Spectra of Multiferroics TbMnO3". Advanced Materials Research 1112 (julio de 2015): 23–26. http://dx.doi.org/10.4028/www.scientific.net/amr.1112.23.

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The dream to have multifunctional materials has triggered an intense study of multiferroicity,i.e.of materials in which magnetic and electric polarizations are simultaneously present and strongly coupled. Here we study TbMnO3, a perovskite manganite exhibiting multiferroicity. It has an incommensurate antiferromagnetic ordering transition at 41 K and a transition into a multiferroic spin spiral state at 26 K. In this study, Raman spectroscopy has been used to elucidate the nature of the excitations related to phase transitions. We show that the optical phonons in TbMnO3resemble the phonon characteristics typical for perovskite manganites, corresponding to MnO6octahedral vibrations. The appearance of a new low energy modes at 32 cm-1, 40 cm-1, and 63 cm-1observed below 41 K signifies the antiferromagentic ordering in TbMnO3. The 32 cm- 1and 63 cm-1are interpreted as spin ordering activated phonon while the 40 cm-1is interpreted as spin ordering induced splitting of Tb quasi doublet cystal field level.
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16

Sardjono, Priyo y Wisnu Ari Adi. "Thermal Analysis and Magnetic Properties of Lanthanum Barium Manganite Perovskite". Advanced Materials Research 896 (febrero de 2014): 381–84. http://dx.doi.org/10.4028/www.scientific.net/amr.896.381.

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The lanthanum manganite is the family of magnetic materials which had the magnetic properties are varied depend on the composition. This study has been carried out synthesis and characterization of thermal and magnetic properties of the lanthanum barium manganite perovskite. The perovskite material is prepared by oxides, namely La2O3, BaCO3, and MnCO3. The mixture was milled for 10h and then sintered at temperature of 1000 °C for 10h. Thermal analysis and magnetic properties are measured by differential thermal analysis (TG-DTA) and vibrating sample magnetometer (VSM), respectively. Decomposition phase of MnCO3become MnO occurred at temperatures around 390 °C with releasing in CO2. Since lanthanum manganite has a stable ion configuration, magnetic properties of these systems are built from MnO phase transformation become α-Mn2O3is arrayed anti-ferromagnetic due to the presence of lanthanum in the system. And this anti-ferromagnetic behavior occurred due to magnetic interactions between Mn3+adjacent ions through super-exchange mechanism. While lanthanum barium manganite had a less stable ion configuration, therefore magnetic properties of these systems are built from phase transformation MnO become α-Mn3O4is arrayed ferromagnetic due to the presence of lanthanum and barium in this system. The presence of lanthanum and barium trigger in the emergence of mixed-valence Mn ions, so that occur to magnetic interaction between Mn3+and Mn4+through the double-exchange mechanism. We concluded that the characteristic of magnetic properties on the lanthanum barium manganite system perovskite is affected by thermal properties, fundamental properties of raw material and the result of reaction is formed.
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17

LANDÍNEZ TÉLLEZ, D. A., L. A. CARRERO BERMÚDEZ, C. E. DELUQUE TORO, R. CARDONA y J. ROA-ROJAS. "CRYSTALLOGRAPHIC, FERROELECTRIC AND ELECTRONIC PROPERTIES OF THE Sr2ZrTiO6 DOUBLE PEROVSKITE". Modern Physics Letters B 27, n.º 20 (agosto de 2013): 1350141. http://dx.doi.org/10.1142/s0217984913501418.

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In this paper, we report structural analysis, ferroelectric behavior and electronic structure of Sr 2 ZrTiO 6 double perovskite. Samples were produced by the solid state reaction recipe. Crystallographic analysis was performed by Rietveld refinement of experimental X-ray diffraction patterns. Results show that this material crystallizes in a tetragonal perovskite structure which corresponds to the space group I4/m. The curve of polarization as a function of applied voltage evidences a ferroelectric character with saturation polarization on the application of voltages up to 1800 V. Calculations of density of states and band structure for this manganite-like material were carried out by means of the density functional theory implemented into the Wien2k code. Results of total and partial density of states reveal the insulator character of this material with an energy gap of 2.66 eV.
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18

Matsukawa, M., R. Sato, H. Ogasawara, M. Yoshizawa, R. Suryanarayanan, G. Dhalenne, A. Revcolevschi y K. Itoh. "Anomalous thermal transport in double-layered perovskite manganite La1.2Sr1.8Mn2O7". Physica B: Condensed Matter 281-282 (junio de 2000): 505–6. http://dx.doi.org/10.1016/s0921-4526(99)01105-9.

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19

Das, Subrata, Irin Sultana, M. D. I. Bhuyan y M. A. Basith. "Enhanced Magnetic Softness of Double-Layered Perovskite Manganite La1.7Gd0.3SrMn2O7". IEEE Magnetics Letters 10 (2019): 1–4. http://dx.doi.org/10.1109/lmag.2019.2915620.

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20

Ayaş, Ali Osman, Mustafa Akyol, Selda Kılıç Çetin, Melike Kaya, İlker Dinçer, Ahmet Ekicibil y Yalçın Elerman. "Room temperature magnetocaloric effect in Pr1.75Sr1.25Mn2O7 double-layered perovskite manganite system". Philosophical Magazine 97, n.º 9 (16 de enero de 2017): 671–82. http://dx.doi.org/10.1080/14786435.2017.1279363.

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21

Wang, Zhiming, Gang Ni y Yulu Che. "Magnetocaloric Effect in Perovskite Manganite La0.65Nd0.05Ba0.3MnO3 with Double Metal–Insulator Peaks". Journal of Superconductivity and Novel Magnetism 25, n.º 2 (21 de octubre de 2011): 533–39. http://dx.doi.org/10.1007/s10948-011-1329-8.

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22

Jin, Shuaizhao, Xiaokun Zhu, Yixin Yan, Xiaohan Yu, Xiaoli Guan, Xin Gu, Kaikai Wu, Liming Zhao y Xiang Liu. "La0.7Na0.3−xKxMnO3 (x = 0.2): A thermistor film that exhibits high-sensitivity at room temperature". Applied Physics Letters 121, n.º 8 (22 de agosto de 2022): 082202. http://dx.doi.org/10.1063/5.0097996.

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A high-sensitivity thermistor La0.7Na0.3− xK xMnO3 ( x = 0.2) film with a perovskite structure was fabricated and studied. The results show that the film displayed excellent adaptation and clear interfaces with the SrTiO3 substrate. Under the combination of Jahn–Teller effect and double exchange mechanism, the temperature coefficient of resistivity ( TCR) of the La0.7Na0.1K0.2MnO3 film reached 10.86% K−1 at 296.98 K. Compared with the conventional VO2 and nickel–manganite-based film materials, the La0.7Na0.1K0.2MnO3 film with high TCR values at room temperature exhibited tunable metal–insulation transition temperature and more sensitive thermal properties. Consequently, the La0.7Na0.1K0.2MnO3 film can substantially improve the detection sensitivity of uncooled infrared bolometers as thermistor materials.
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23

Ogasawara, Hiromitsu, Michiaki Matsukawa, Sigeru Hatakeyama, Masahito Yoshizawa, M. Apostu, R. Suryanarayanan, G. Dhalenne, A. Revcolevschi, Kikuo Itoh y Norio Kobayashi. "Anomalous Lattice Distortion in Pr-Substituted Double-Layered Perovskite Manganite La1.2Sr1.8Mn2O7Single Crystals". Journal of the Physical Society of Japan 69, n.º 5 (15 de mayo de 2000): 1274–77. http://dx.doi.org/10.1143/jpsj.69.1274.

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24

Ogasawara, H., M. Matsukawa, M. Yoshizawa, M. Apostu, R. Suryanarayanan, G. Dhalenne, A. Revcolevschi, K. Itoh y N. Kobayashi. "Giant magnetostriction in Pr-substituted double-layered perovskite manganite La1.2Sr1.8Mn2O7 single crystals". Journal of Magnetism and Magnetic Materials 226-230 (mayo de 2001): 990–92. http://dx.doi.org/10.1016/s0304-8853(01)00109-3.

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25

Bhatti, Ilyas Noor y Imtiaz Noor Bhatti. "Spin-phonon coupling and dielectric spectroscopy in nano-crystalline Pr2CoMnO6 double perovskite manganite". Physica B: Condensed Matter 610 (junio de 2021): 412943. http://dx.doi.org/10.1016/j.physb.2021.412943.

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26

Matsukawa, Michiaki, Hiromitsu Ogasawara, Toru Sasaki, Masahito Yoshizawa, M. Apostu, R. Suryanarayanan, A. Revcolevschi, Kikuo Itoh y Norio Kobayashi. "Anomalous Lattice Distortion in Pr-Substituted Double-Layered Perovskite Manganite La1.2Sr1.8Mn2O7Single Crystals: II". Journal of the Physical Society of Japan 71, n.º 6 (15 de junio de 2002): 1475–80. http://dx.doi.org/10.1143/jpsj.71.1475.

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27

Гудин, С. А. "Аномальное изменение размера спинового полярона в парамагнитной области температур в La-=SUB=-1.2-=/SUB=-Sr-=SUB=-1.8-=/SUB=-Mn-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=-". Физика твердого тела 63, n.º 12 (2021): 1978. http://dx.doi.org/10.21883/ftt.2021.12.51653.31s.

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In this work, we continued the study of the magnetic and electrical properties of the double perovskite La1.2Sr1.8Mn2O7, which has a colossal magnetoresistance in excess of 1200 near the Curie temperature. It is shown that the colossal magnetoresistance observed in La1.2Sr1.8Mn2O7 is well described on the basis of the “orientational” and “spin-polaron” conduction mechanisms. It was found in the work that in the absence of a magnetic field, the linear size of the spin polaron decreases with increasing temperature in the ferromagnetic region, and upon the transition of manganite to the paramagnetic state, the linear size begins to increase, reaching a maximum at 180 K. At temperatures exceeding 180 K, an anomalous temperature change the size of the spin polaron disappears. In the absence of a magnetic field, the detected peak on the temperature curve of the change in the size of the spin polaron is maximal; with the inclusion of the magnetic field, the peak height decreases. Mechanisms are proposed to explain this anomalous temperature behavior of the spin polaron size.
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28

Argyriou, D. N., J. F. Mitchell, J. D. Jorgensen, J. B. Goodenough, P. G. Radaelli, D. E. Cox y H. N. Bordallo. "Structure and Magnetism in the Layered CMR Manganites La2-2xSr1+2xMn2O7 (x= 0·3, 0·4)". Australian Journal of Physics 52, n.º 2 (1999): 279. http://dx.doi.org/10.1071/p98105.

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In this paper we describe a detailed neutron diffraction investigation of the crystal and magnetic structure of two layered CMR manganites La1·2Sr1·8Mn2O7 (x = 0·4) and La1·4Sr1·6Mn2O7 (x = 0·3). In these materials of reduced dimensionality compared to the 3D perovskites, we find competing effects between charge-lattice and spin degrees of freedom. These effects can be investigated by studying the behaviour of crystal and magnetic structure as a function of temperature, composition and hydrostatic pressure. We find opposite lattice responses to the onset of charge delocalisation and magnetic ordering in these two layered compounds. Below the insulator-to-metal transition (TIM), the lattice response suggests that charge is transferred to d3z2-r2 orbitals in La1·2Sr1·8Mn2O7 and to dx2-y2 orbitals in La1·4Sr1·6Mn2O7. We argue that these changes are too large to be due to chemical differences. Instead we suggest that the orbital configuration of the Mn ion below TIM is sensitive to electronic doping. In La1·2Sr1·8Mn2O7 we find that the lattice response at TIM to be driven by lattice displacements that relax below TIM, consistent with polaronic degrees of freedom. We also note that the competition between super- and double-exchange to be significant in reduced dimensions. This is manifested in the change in the sign of the apical Mn-O bond compressibilities above and below TIM. Finally, we describe the magnetic structure of these two different layered manganites. We find that electronic doping also results in significant changes to the ordered arrangement of Mn spins. Interestingly the magnetism in reduced dimensions in these materials can be varied from relative simple structures that show ferromagnetic inter-bilayer coupling as observed in La1·2Sr1·8Mn2O7 to structures with antiferromagnetic inter-bilayer coupling as found in La1·4Sr1·6Mn2O7.
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29

Ayaş, Ali Osman. "Observation of Room-Temperature Range Magnetocaloric Effect in PrSr1−xPbxMn2O6 (0.4 ≤ x ≤ 0.6) Double-Perovskite Manganite System". Journal of Superconductivity and Novel Magnetism 32, n.º 2 (18 de mayo de 2018): 393–403. http://dx.doi.org/10.1007/s10948-018-4688-6.

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30

Ayaş, Ali Osman. "Structural and magnetic properties with reversible magnetocaloric effect in PrSr1–xPbxMn2O6 (0.1 ≤ x ≤ 0.3) double perovskite manganite structures". Philosophical Magazine 98, n.º 30 (31 de julio de 2018): 2782–96. http://dx.doi.org/10.1080/14786435.2018.1503424.

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31

Ayaş, Ali Osman, Arda Kandemir, Selda Kılıç Çetin, Gönül Akça, Mustafa Akyol y Ahmet Ekicibil. "Investigation of the effect of sintering temperature on structural, magnetic and magnetocaloric properties in PrCaMn2O6 double perovskite manganite system". Journal of Materials Science: Materials in Electronics 33, n.º 10 (25 de febrero de 2022): 7357–70. http://dx.doi.org/10.1007/s10854-022-07843-4.

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32

Rusakov, V. S., I. A. Presniakov, T. V. Gubaidulina, A. V. Sobolev, A. V. Baranov, G. Demazeau y K. M. Veselova. "57Fe and 119Sn probe Mössbauer spectroscopy investigation of perovskite-type double manganite family CaCu x Mn7−x O12 (x = 0, 0.15, 3)". Bulletin of the Russian Academy of Sciences: Physics 75, n.º 2 (febrero de 2011): 271–76. http://dx.doi.org/10.3103/s1062873810031037.

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33

Padhan, P., N. K. Pandey, S. Srivastava, R. K. Rakshit, V. N. Kulkarni y R. C. Budhani. "Transition from a double exchange ferromagnetic metal to hysteretic insulator mimicking charge ordering effects in ultra-thin epitaxial films of a perovskite manganite". Solid State Communications 117, n.º 1 (noviembre de 2000): 27–32. http://dx.doi.org/10.1016/s0038-1098(00)00422-1.

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34

Su, Jianliang, Chengwei Cai y Mei Ji. "An investigation on strain and magnetic properties of perovskite manganite superlattice films". International Journal of Modern Physics B, 4 de marzo de 2023. http://dx.doi.org/10.1142/s021797922450036x.

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The mixed-valence perovskite manganites attracted much attention because of their interesting electro-magnetic properties, and strain modulation on magnetic properties of perovskite manganites is worth exploring. In this paper, [La[Formula: see text]Ca[Formula: see text]MnO3/La[Formula: see text]Ca[Formula: see text]MnO3][Formula: see text] superlattice films with different La[Formula: see text]Ca[Formula: see text]MnO3 layer thicknesses are prepared by pulsed laser deposition (PLD). The crystal structures (lattice constants) of samples are measured by [Formula: see text]-ray diffraction (XRD). The strain of the films is determined according to their crystal structures. The magnetic hysteresis loops (M-H loops) and magnetization versus temperature (M-T) curves of these superlattice films are measured by the physical property measurement system (PPMS). From the M-H loops, the coercive field (H[Formula: see text] of the samples can be measured. From the M-T curves, the Curie temperature (T[Formula: see text] of the samples can be obtained. All samples show a ferromagnetic to paramagnetic transition at TC, and the [La[Formula: see text]Ca[Formula: see text]MnO3/La[Formula: see text]Ca[Formula: see text]MnO3][Formula: see text] sample with the La[Formula: see text]Ca[Formula: see text]MnO3 layer thicknesses of 72[Formula: see text]Å has an antiferromagnetic Néel transition at TN. According to the strain state and magnetic phases, the magnetic properties are comprehensively analyzed. It is found that with the increase of ferromagnetic La[Formula: see text]Ca[Formula: see text]MnO3 layer thickness, the ferromagnetic phase is increased, and the double exchange effect can also be enhanced, resulting in the increase of TC. When the thickness of La[Formula: see text]Ca[Formula: see text]MnO3 reaches 96[Formula: see text]Å, the uneven strain distribution in the superlattice can induce the reduction of ferromagnetic phase compared with antiferromagnetic phase (even antiferromagnetic phase starts to appear), and the double exchange effect can be weakened, and finally leading to the decrease of TC. In addition, with increasing the La[Formula: see text]Ca[Formula: see text]MnO3 layer thickness, HC gradually decreases. The change of HC is related to strain states and magnetic phase interactions in the samples. The analysis of the strain and magnetism can contribute to the understanding of perovskite manganite superlattice films.
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35

Su, Ying y Shi-Zeng Lin. "Nontrivial topology and localization in the double exchange model with possible applications to perovskite manganites". Physical Review B 98, n.º 23 (7 de diciembre de 2018). http://dx.doi.org/10.1103/physrevb.98.235116.

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36

Paul, Sanjoy y Tapan K. Nath. "Magneto-transport and Magnetic Properties of Fe Doped Nanometric Polycrystalline La0.7Sr0.3MnO3 CMR Manganites". MRS Proceedings 1183 (2009). http://dx.doi.org/10.1557/proc-1183-ff11-01.

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AbstractWe have investigated the effect of 3d-transition metal Fe (Iron) doping at Mn site of nanometric polycrystalline La0.7Sr0.3MnO3 (i.e. La0.7Sr0.3Mn1-xFexO3; 0 ≤ x ≤ 0.1) CMR manganites on magneto-transport and magnetic properties. Nanocrystalline Fe doped La0.7Sr0.3MnO3 powders were synthesized through chemical route “Pyrophoric Reaction Process” and calcinated at 850°C for 5 hrs. X-ray diffraction (XRD) patterns of synthesized powder indicate that all samples are having perovskite structure without any secondary impurity phase. Average crystallite size was found to be 20 nm using Debye Scherer formula. Transmission electron micrographs (TEM) show that the average particle sizes are in nanometric regime (φ ˜ 50 nm) and samples are polycrystalline in nature which was observed through selected area electron diffraction (SEAD) patterns. The effect of Fe doping at Mn site of La0.7Sr0.3MnO3 was found to change substantially the magnetic and transport properties without modifying lattice structure. The suppression of magnetic and transport properties were observed due to dilution of double exchange mechanism in Mn3+- O2--Mn4+ network in La0.7Sr0.3MnO3.
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37

Huang, S. J., J. D. Liu, Z. W. Pan, H. J. Zhang y B. J. Ye. "Effect of intrinsic vacancies on the electromagnetic properties of half-doped Sm0.5Ca0.5MnO3 manganites studied by positron annihilation". Journal of Applied Physics 134, n.º 6 (9 de agosto de 2023). http://dx.doi.org/10.1063/5.0157773.

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Mixed valence manganites are potential functional materials due to their unique electromagnetic properties. In this work, half-doped ceramics with the perovskite structure Sm0.5Ca0.5MnO3 polycrystalline samples are synthesized by the solid-state reaction method in open air at different final sintering temperatures. Structures and particle sizes are studied by x-ray diffraction and scanning electron microscopy, respectively. Positron annihilation spectroscopy and density-functional theory calculations are used to characterize the intrinsic vacancies in the bulk. Thereafter, the effect of vacancies on the magnetic and magnetoresistance (MR) properties is investigated. We find that Mn monovacancies (VMn) exist in the bulk among all the samples, and the concentration of VMn is different. We suggest a possible defect model that can be well applied to explain the phenomena of their electromagnetic properties. The transition temperature of the charge-order state (TCO) and ferromagnetic and anti-ferromagnetic (TN) are most likely related to the concentration of VMn and the particle sizes or pore sizes, respectively. The glass spin state transition temperature seems to be independent of the defect concentration and type. The metal conductive behavior does not appear in a high magnetic field and at low temperatures, which may be caused by the presence of a high concentration of VMn in the bulk and oxygen-related defects in the boundary, and the double exchange interaction is suppressed. At temperatures below TN and under a weak magnetic field, the MR is related to the total defect concentration. In addition, the high concentration of VMn is unfavorable for obtaining a high MR value.
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38

Sikkema, Rebecca y Igor Zhitomirsky. "Magnetic supercapacitors: Charge storage mechanisms, magnetocapacitance, and magnetoelectric phenomena". Applied Physics Reviews 10, n.º 2 (5 de mayo de 2023). http://dx.doi.org/10.1063/5.0134593.

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Pseudocapacitive (PC) materials are under investigation for energy storage in supercapacitors, which exhibit exceptionally high capacitance, good cyclic stability, and high power density. The ability to combine high electrical capacitance with advanced ferrimagnetic or ferromagnetic properties in a single material at room temperature opens an avenue for the development of advanced magnetically ordered pseudocapacitive (MOPC) materials. This review covers materials science aspects, charge storage mechanisms, magnetocapacitance, and magnetoelectric (ME) phenomena in MOPC materials. Recent studies demonstrate high PC properties of advanced ferrimagnetic materials, such as spinel ferrites and hexagonal ferrites. Of particular importance is the discovery of PC properties of perovskite-type manganites, which exhibit room temperature ferromagnetism and giant negative magnetoresistance. The coupling of high capacitance and magnetization in MOPC provides a platform for strong ME interactions. Various strategies are used for manipulation of electrical capacitance/magnetization of MOPC by a magnetic field/electrode potential. Magnetocapacitance studies show significant increase in capacitance of MOPC under the influence of a magnetic field. Moreover, the application of a magnetic field results in enhanced energy density and power density, reduction of resistance, and improvement of cyclic stability. Such findings offer a potential of a breakthrough in the development of advanced supercapacitors. High magnetocapacitance and ME phenomena are linked to the influence of magnetic fields on electrolyte diffusion, structure of electrical double layer, charge transfer resistance, and variation of conductivity and magnetization of MOPC materials, which facilitate charge/discharge behavior. Various applications of ME effect in MOPC are discussed. Moreover, advantages of magnetocapacitive MOPC are described for applications in electronic and spintronic devices, supercapacitors, and devices for magnetically enhanced capacitive deionization of water.
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39

Ogale, S. B., S. R. Shinde, T. Venkatesan y R. Ramesh. "Manganite, Magnetite, and Double-Perovskite Thin Films and Heterostructures". ChemInform 37, n.º 26 (27 de junio de 2006). http://dx.doi.org/10.1002/chin.200626198.

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40

Yamada, S., N. Abe, H. Sagayama, K. Ogawa, T. Yamagami y T. Arima. "Room-Temperature Low-Field Colossal Magnetoresistance in Double-Perovskite Manganite". Physical Review Letters 123, n.º 12 (17 de septiembre de 2019). http://dx.doi.org/10.1103/physrevlett.123.126602.

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41

Sterkhov, Evgenii V., Nikolay M. Chtchelkatchev, Elena V. Mostovshchikova, Roman E. Ryltsev, Sergey A. Uporov, Gheorghe L. Pascut, Andrey V. Fetisov y Svetlana G. Titova. "The origin of the structural transition in double-perovskite manganite PrBaMn2O6". Journal of Alloys and Compounds, septiembre de 2021, 162034. http://dx.doi.org/10.1016/j.jallcom.2021.162034.

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42

Hanna, Farid y Peter Ibrahim. "Double-doping Effect on Structural and Magnetic Properties of Perovskite Lanthanum Manganite". ECS Journal of Solid State Science and Technology, 28 de junio de 2022. http://dx.doi.org/10.1149/2162-8777/ac7c8d.

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Abstract Polycrystalline samples La(2+4x) /3Sr(1-4x) /3Mn1-xCuxO3 (x = 0, 0.1, 0.15 and 0.25) with double doping in the A site and B site were successfully prepared by the conventional solid-state reaction method with heat treatment up to 1300oC. All the obtained samples consist of single perovskite phase with a rhombohedral symmetry and R3 ̅C space group. The (a) lattice parameter and the volume of the unit cell were found to increase with the increase of Cu doping level (x). The morphology of the prepared samples was studied by scanning electron microscope imaging, and the stoichiometry of the compositions was confirmed. The hysteresis loops at room temperature for x = 0, 0.1 and 0.15 samples are characteristic for soft ferromagnetic materials, with a decrease of the ferromagnetic interaction and a decrease of the magnetic moment with the increase of Cu doping level. No ferromagnetic behavior was detected at room temperature for the x = 0.25 sample. The question of the valency of Cu ions was discussed during the present study. Our results are best interpreted by assuming the coexistence of Cu2+ and Cu3+ ions.
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43

Kwei, G. H., D. N. Argyriou, S. J. L. Billinge, A. C. Lawson, J. J. Neumeier, A. P. Ramirez, M. A. Subramanian y J. D. Thompson. "Lattice Effects in Perovskite and Pyrochlore CMR Materials". MRS Proceedings 475 (1997). http://dx.doi.org/10.1557/proc-475-533.

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ABSTRACTColossal magnetoresistance (CMR) in doped lanthanum manganite thin films (Lai.xMx, where M is a divalent ion) has been shown to result in a factor of 106 suppression of the resistance. The driving force for the CMR transition is thought to be the double-exchange (DE) interaction. Many studies of both the crystal structure and the local structure of the Lai.xMxMnO3 (with M = Ca, Sr and Ba, as well as Pb) system have now been carried out. As expected, these systems all show a strong coupling of the lattice to the CMR transition. On the other hand, neutron diffraction data and x-ray absorption studies for the Ti2mn2O7 pyrochlore, which also exhibits CMR, shows no deviations from ideal stoichiometry, mixed valency, or Jahn-Teller distortions of the MnO6 octahedron. We present results of crystallographic and local structural studies of these two important classes of CMR materials. compare the differences in structural response, and discuss the implications of these findings to our understanding of these materials.
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44

"Sol–Gel Synthesis, Characterization, and Magnetic Properties of Double-Layered Perovskite Manganite La1.25Sr1.75Mn2O7". IEEE Transactions on Magnetics 50, n.º 6 (junio de 2014): 1–4. http://dx.doi.org/10.1109/tmag.2014.2308482.

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45

Shekhtman, V. Sh, V. Sedykh, N. S. Afonikova, A. V. Dubovitskii y V. I. Kulakov. "The electron microscopy and XRD investigation of structure processes in CMR crystals LaMnO3+δ". MRS Proceedings 839 (2004). http://dx.doi.org/10.1557/proc-839-p3.5.

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ABSTRACTThe specific features of structural transformations in lanthanum manganite are analyzed in terms of the macrosymmetry conservation principle. The possible mechanisms of phase transformations are proposed reasoning from a sequence of structural transitions, including the restoration of a virtual configuration of cubic perovskite with double the lattice parameter. It has been synthesized and investigated three phases Pnma I, Pnma II, R3c. It has been shown by X-ray diffraction analysis and Mössbauer spectroscopy that the transition from the Pnma I to Pnma II phase in LaMnO3+d compound occurs through the intermediate phase Pnma II* virtually by “jump”. The HEED investigations of the synthesized phases have shown that the Pnma I and R3c phases have the expected simple pattern whereas the electron-diffraction pattern of the Pnma II phase strongly differs.
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46

SEVER, İbrahim Barış, Arda KANDEMİR, Ali Osman AYAŞ y Ahmet EKİCİBİL. "The Effect of Sintering Temperature on Magnetic Cooling Parameters in La2MnNiO6 Double Perovskite Manganite Material". Adıyaman University Journal of Science, 9 de agosto de 2023. http://dx.doi.org/10.37094/adyujsci.1329921.

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La2NiMnO6 çift-katlı perovskit manganit sistemi sol-jel yöntemi ile üretilmiş, LNM-1000 örneği 1000 ˚C'de, LNM-1100 örneği ise 1100 ˚C'de sinterlenmiştir. Üretilen örneklerin yapısal, morfolojik, manyetik ve manyetokalorik özellikleri incelenmiştir. Numunelerin kristal yapısının Rombohedral yapıda ve R3 ̅c uzay grubunda olduğu belirlendi. Morfolojik özellikleri incelendiğinde LNM-1000 numunesinin küçük yapılı, çok köşeli ve düzensiz şekilli taneler içerdiği, LNM-1100 numunesi içinse bu bilgilerin yanında bazı yerlerde tane sınırlarının belirsizleştiği görülmektedir. LNM-1000 ve LNM-1100 numuneleri için Curie sıcaklıkları 200 ve 220 K olarak belirlenirken efektif manyetik moment değerleri sırasıyla 1.75 ve 2.13 B olarak hesaplanmıştır. Arrot grafikleri, numunelerin ikinci dereceden manyetik faz geçişi sergilediğini göstermektedir. Maksimum manyetik entropi değişimi ve bağıl soğutma gücü değerleri LNM-1000 ve LNM-1100 numuneleri için sırasıyla 0,21, 0,25 J kg-1 K-1 ve 46,2, 50,5 J kg-1 olarak hesaplanmıştır. Örnekler Gd2NiMnO6 örneğinden (5 K) çok daha yüksek olan oda altı sıcaklık aralığında Curie sıcaklığına ve ikinci dereceden manyetik faz geçişine sahip olmalarına rağmen, nispeten düşük manyetik entropi değişim değerleri, manyetik soğutucu malzeme olarak kullanımlarını sınırlandırmaktadır.
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47

Han, Jiamei, Xiaohan Yu, Shuaizhao Jin, Xiaoli Guan, Xin Gu, Yixin Yan, Kaikai Wu et al. "Nd1-Sr MnO3 (x = 0.3): A perovskite manganite ceramic that exhibits PTC and NTC double properties". Ceramics International, septiembre de 2022. http://dx.doi.org/10.1016/j.ceramint.2022.09.325.

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48

"Foreword". Australian Journal of Physics 52, n.º 2 (1999): 151. http://dx.doi.org/10.1071/phv52n2_fo.

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In this paper we describe a detailed neutron diffraction investigation of the crystal and magnetic structure of two layered CMR manganites La1·2Sr1·8Mn2O7 (x = 0·4) and La1·4Sr1·6Mn2O7 (x = 0·3). In these materials of reduced dimensionality compared to the 3D perovskites, we find competing effects between charge-lattice and spin degrees of freedom. These effects can be investigated by studying the behaviour of crystal and magnetic structure as a function of temperature, composition and hydrostatic pressure. We find opposite lattice responses to the onset of charge delocalisation and magnetic ordering in these two layered compounds. Below the insulator-to-metal transition (TIM), the lattice response suggests that charge is transferred to d3z2-r2 orbitals in La1·2Sr1·8Mn2O7 and to dx2-y2 orbitals in La1·4Sr1·6Mn2O7. We argue that these changes are too large to be due to chemical differences. Instead we suggest that the orbital configuration of the Mn ion below TIM is sensitive to electronic doping. In La1·2Sr1·8Mn2O7 we find that the lattice response at TIM to be driven by lattice displacements that relax below TIM, consistent with polaronic degrees of freedom. We also note that the competition between super- and double-exchange to be significant in reduced dimensions. This is manifested in the change in the sign of the apical Mn-O bond compressibilities above and below TIM. Finally, we describe the magnetic structure of these two different layered manganites. We find that electronic doping also results in significant changes to the ordered arrangement of Mn spins. Interestingly the magnetism in reduced dimensions in these materials can be varied from relative simple structures that show ferromagnetic inter-bilayer coupling as observed in La1·2Sr1·8Mn2O7 to structures with antiferromagnetic inter-bilayer coupling as found in La1·4Sr1·6Mn2O7.
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49

Tanaka, Hidekazu, Jun Zhang y Tomoji Kawai. "Giant Electric Field Modulation of Double Exchange Ferromagnetism at Room Temperature in the Perovskite Manganite/Titanatep−nJunction". Physical Review Letters 88, n.º 2 (27 de diciembre de 2001). http://dx.doi.org/10.1103/physrevlett.88.027204.

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50

Krishnan, Kannan M., H. L. Ju, H. C. Sohn, C. Nelson y A. R. Modak. "New Insights into The Transport and Field-Enhancement Effects in Sol-Gel Derived Colossal Magnetoresistive Thin Films". MRS Proceedings 474 (1997). http://dx.doi.org/10.1557/proc-474-139.

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ABSTRACTThe transport mechanism underlying the colossal magnetoresistance (CMR) of doped manganites is not yet understood and their technological applications are limited by the high fields (∼IT) required to obtain any significant MR. Following the development of a polymeric chemical synthesis route, we have investigated the O2p unoccupied density of states in sol-gel derived Lal-xSrxMnO3 (0 < x < 0.7) thin films grown epitaxially on LaA1O3, by electron energy-loss spectroscopy at sub-eV resolution. The spectra show a distinct prepeak in the OK edge at the Fermi level, the intensity of which correlates directly with the conductivity of the film. Similar correlation was also obtained for La0.7Sr0.3MnO3-z annealed in vacuum to obtain well defined oxygen content (z) in the film. This confirms that the charge carriers in these manganese perovskites have significant oxygen 2p hole character and suggests that the “double exchange” mechanism has to be modified. In another set of experiments we have studied room-temperature field amplification effects to enhance the low-field sensitivity of La0.7Sr0.3MnO3-z films sandwiched between two thin rectangular slices of either α-Fe or Mn-Zn ferrite. This field amplification leads to an enhanced low-field MR value as high as 6% at an external field of 500 Oe which is 6 times the value observed without the amplification.
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