The Experts below are selected from a list of 79650 Experts worldwide ranked by ideXlab platform
Zhao-hua Cheng - One of the best experts on this subject based on the ideXlab platform.
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anisotropic magnetic entropy change in rfeo3 single crystals r tb tm or y
Scientific Reports, 2016Co-Authors: Xiangqun Zhang, Zhao-hua ChengAbstract:Compared with traditional gas-compression/expansion refrigeration, magnetic refrigeration based on magnetocaloric effect (MCE) exhibits the advantages of high energy efficiency and environment friendliness. Here, we created large MCE in RFeO3 (R = Tb or Tm) single crystals by the magnetization vector rotation of single crystal with strong magnetocrystalline anisotropy (MCA), rather than merely via the order-disorder magnetic phase transition or magnetic structural transition. Owing to the difference in charge distribution of 4f-electrons between Tb3+ and Tm3+ ions, the Rotating Field entropy with different signs, −ΔSMR = 17.42 J/kg K, and –ΔSMR = −9.01 J/kg K are achieved at 9 K and 17 K for TbFeO3 and TmFeO3 single crystals from b axis to c axis, at 50 kOe, respectively. The finding of the large anisotropic MCE not only advances our understanding of the anisotropy of MCE, but also extends the application for single crystals to magnetic refrigeration.
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low Field induced giant anisotropic magnetocaloric effect in dyfeo3 single crystal
Chinese Physics B, 2015Co-Authors: Xiangqun Zhang, Zhao-hua ChengAbstract:We have investigated the anisotropic magnetocaloric effect and the Rotating Field magnetic entropy in DyFeO3 single crystal. A giant Rotating Field entropy change of was achieved from b axis to c axis in bc plane at 5 K for a low Field change of 20 kOe. The large anisotropic magnetic entropy change is mainly accounted for the 4f electron of rare-earth Dy3 + ion. The large value of Rotating Field entropy change, together with large refrigeration capacity and negligible hysteresis, suggests that the multiferroic ferrite DyFeO3 singlecrystal could be a potential material for anisotropic magnetic refrigeration at low Field, which can be realized in the practical application around liquid helium temperature region.
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Rotating Field entropy change in hexagonal tmmno3 single crystal with anisotropic paramagnetic response
Physical Review B, 2012Co-Authors: Jinling Jin, Xiangqun Zhang, Zhao-hua ChengAbstract:The anisotropy of magnetic Field- induced entropy change, -Delta S, was investigated in a hexagonal TmMnO3 single crystal at a temperature range of 2-50 K. The value of -Delta S along the c axis reaches a maximum of 8.73 J/kg K at 17 K in a Field of 70 kOe, which is 20 times larger than that along the a axis. Our finding suggests that the Rotating Field entropy change -Delta S-R(alpha) from the a to c axis is attributed not only to magnetocrystalline anisotropy, but to thermal fluctuations.
Franz G Mertens - One of the best experts on this subject based on the ideXlab platform.
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controlled vortex core switching in a magnetic nanodisk by a Rotating Field
Journal of Applied Physics, 2007Co-Authors: Volodymyr P Kravchuk, Denis D Sheka, Yuri Gaididei, Franz G MertensAbstract:The control of the vortex state magnetic nanoparticle by ultrafast magnetic Fields is studied theoretically. Using the micromagnetic simulations for the Permalloy nanodisk we demonstrate that the vortex core magnetization can be irreversible switched by the alternating Field, Rotating in the disk plane, with the frequency about 10 GHz and intensity about 20 mT. We propose an analytical picture of such phenomena involving the creation and annihilation of vortex-antivortex pairs and calculate the phase diagram of the Fields parameters leading to the switching.
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controlled vortex core switching in a magnetic nanodisk by a Rotating Field
arXiv: Strongly Correlated Electrons, 2007Co-Authors: Volodymyr P Kravchuk, Denis D Sheka, Yuri Gaididei, Franz G MertensAbstract:The switching process of the vortex core in a Permalloy nanodisk affected by a Rotating magnetic Field is studied theoretically. A detailed description of magnetization dynamics is obtained by micromagnetic simulations.
Edward Della Torre - One of the best experts on this subject based on the ideXlab platform.
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rotational magnetization losses in vector models
Journal of Applied Physics, 2003Co-Authors: Edward Della TorreAbstract:Unlike the case of an oscillating magnetic Field, power losses in a magnetic material eventually start decreasing as the magnitude of a Rotating Field increases. In some hysteresis models, the loss increases monotonically as the magnitude of a Rotating Field increases. The simplified vector Preisach model and the reduced vector Preisach model do not suffer from this error. For magnetization-dependent reversible models, such as the Della Torre-Oti-Kadar, and for state-dependent models such as the complete moving model, the loss per cycle has two components. The first is computed from the Preisach integrals, and the second is computed from the change in the stored energy in the reversible component. It is noted that the latter loss can occur even if there are no Barkhausen jumps. This article discusses the details of how the model accomplishes this.
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isotropic media and the simplified vector preisach model
Physica B-condensed Matter, 2001Co-Authors: Edward Della Torre, Ann ReimersAbstract:This paper addresses an orientation error discovered when the simplified vector Preisach model (SVPM) was applied to an isotropic medium. For a smoothly Rotating Field, the magnetization of an isotropic medium should rotate smoothly. Instead, the SVPM predicts a ratcheting motion. A correction for this problem is suggested.
A. Schneidewind - One of the best experts on this subject based on the ideXlab platform.
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Field-Angle-Resolved Magnetic Excitations as a Probe of Hidden-Order Symmetry in CeB 6
Physical Review X, 2020Co-Authors: P. y. Portnichenko, A. Akbari, S. e. Nikitin, A. s. Cameron, A. v. Dukhnenko, V. b. Filipov, N. yu. Shitsevalova, P. Čermák, I. Radelytskyi, A. SchneidewindAbstract:In contrast to magnetic order formed by electrons' dipolar moments, ordering phenomena associated with higher-order multipoles (quadrupoles, octupoles, etc.) are more difficult to characterize because of the limited choice of experimental probes that can distinguish different multipolar moments. The heavy-fermion compound CeB 6 and its La-diluted alloys are among the best-studied realizations of the long-range-ordered multipolar phases, often referred to as "hidden order". Previously the hidden order in phase II was identified as primary antiferroquadrupolar (AFQ) and Field-induced octupolar (AFO) order. Here we present a combined experimental and theoretical investigation of collective excitations in the phase II of CeB 6. Inelastic neutron scattering (INS) in Fields up to 16.5 T reveals a new high-energy mode above 14 T in addition to the low-energy magnetic excitations. The experimental dependence of their energy on the magnitude and angle of the applied magnetic Field is compared to the results of a multipolar interaction model. The magnetic excitation spectrum in Rotating Field is calculated within a localized approach using the pseudo-spin presentation for the Γ 8 states. We show that the Rotating-Field technique at fixed momentum can complement conventional INS measurements of the dispersion at constant Field and holds great promise for identifying the symmetry of multipolar order parameters and the details of inter-multipolar interactions that stabilize hidden-order phases.
Xiangqun Zhang - One of the best experts on this subject based on the ideXlab platform.
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anisotropic magnetic entropy change in rfeo3 single crystals r tb tm or y
Scientific Reports, 2016Co-Authors: Xiangqun Zhang, Zhao-hua ChengAbstract:Compared with traditional gas-compression/expansion refrigeration, magnetic refrigeration based on magnetocaloric effect (MCE) exhibits the advantages of high energy efficiency and environment friendliness. Here, we created large MCE in RFeO3 (R = Tb or Tm) single crystals by the magnetization vector rotation of single crystal with strong magnetocrystalline anisotropy (MCA), rather than merely via the order-disorder magnetic phase transition or magnetic structural transition. Owing to the difference in charge distribution of 4f-electrons between Tb3+ and Tm3+ ions, the Rotating Field entropy with different signs, −ΔSMR = 17.42 J/kg K, and –ΔSMR = −9.01 J/kg K are achieved at 9 K and 17 K for TbFeO3 and TmFeO3 single crystals from b axis to c axis, at 50 kOe, respectively. The finding of the large anisotropic MCE not only advances our understanding of the anisotropy of MCE, but also extends the application for single crystals to magnetic refrigeration.
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low Field induced giant anisotropic magnetocaloric effect in dyfeo3 single crystal
Chinese Physics B, 2015Co-Authors: Xiangqun Zhang, Zhao-hua ChengAbstract:We have investigated the anisotropic magnetocaloric effect and the Rotating Field magnetic entropy in DyFeO3 single crystal. A giant Rotating Field entropy change of was achieved from b axis to c axis in bc plane at 5 K for a low Field change of 20 kOe. The large anisotropic magnetic entropy change is mainly accounted for the 4f electron of rare-earth Dy3 + ion. The large value of Rotating Field entropy change, together with large refrigeration capacity and negligible hysteresis, suggests that the multiferroic ferrite DyFeO3 singlecrystal could be a potential material for anisotropic magnetic refrigeration at low Field, which can be realized in the practical application around liquid helium temperature region.
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Rotating Field entropy change in hexagonal tmmno3 single crystal with anisotropic paramagnetic response
Physical Review B, 2012Co-Authors: Jinling Jin, Xiangqun Zhang, Zhao-hua ChengAbstract:The anisotropy of magnetic Field- induced entropy change, -Delta S, was investigated in a hexagonal TmMnO3 single crystal at a temperature range of 2-50 K. The value of -Delta S along the c axis reaches a maximum of 8.73 J/kg K at 17 K in a Field of 70 kOe, which is 20 times larger than that along the a axis. Our finding suggests that the Rotating Field entropy change -Delta S-R(alpha) from the a to c axis is attributed not only to magnetocrystalline anisotropy, but to thermal fluctuations.
