<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>H</mml:mi><mml:mtext>−</mml:mtext><mml:mi>T</mml:mi></mml:mrow></mml:math>
 phase diagram of rare-earth–transition-metal alloys in the vicinity of the compensation point

Davydova, Margarita; Zvezdin, K. A.; Becker, J. J.; Kimel, A.V.; Zvezdin, A. K.

doi:10.1103/physrevb.100.064409

Cited by 25 publications

(19 citation statements)

References 41 publications

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“…Earlier studies of rare-earth ferrimagnets have found that in the case of weak rare-earth magnetic anisotropy the transition shifts towards the lower temperatures with the increase of the magnetic field 35 . On the other hand, from more general considerations we have shown 19,26,36 that if the rare-earth anisotropy is prevailing an inclination of the first-order phase transition line towards higher temperatures would occur; therefore, we assume that the surface anisotropy introduced by Ta capping influences d-states that relatively more delocalized, and thus, for Ta-coated TbFeCo the f-sublattice anisotropy doesn't dominate at least in the vicinity of the compensation temperature of the film. The physical reason behind this is that Ta, electronic configuration of which is [Xe] 4f 14 5d 3 6s 2 , has large atomic number Z = 73 and spin-orbit coupling scales approximately as Z 4 [ 37 ].…”

Section: Discussionmentioning

confidence: 94%

Unusual Field Dependence of the Anomalous Hall Effect in Ta/Tb−Fe−Co

et al. 2020

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Experimental studies of anomalous Hall effect are performed for thin filmed Ta/TbFeCo in a wide range of temperatures and magnetic fields up to 3 T. While far from the compensation temperature (T M =277 K) the field dependence has a conventional shape of a single hysteresis loop, just below the compensation point the dependence is anomalous having the shape of a triple hysteresis. To understand this behavior, we experimentally reveal the magnetic phase diagram and theoretically analyze it in terms of spinreorientation phase transitions. We show that one should expect anomalous hysteresis loops below the compensation point if in the vicinity of it the magnetic anisotropy is dominated by FeCo sublattice due to interaction with Ta. 19 , here the situation is inverted that the triple hysteresis is observed below T M . More particularly, using Hall bar structures of MgO/Ta/TbFeCo we measured field dependencies

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Section: Discussionmentioning

confidence: 94%

Unusual Field Dependence of the Anomalous Hall Effect in Ta/Tb−Fe−Co

et al. 2020

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“…, where g is Lande g-factor, J is total angular momentum of the rare-earth ions, µ B is Bohr magneton. The anisotropy energy of the ferrimagnet is [14,19]:…”

Section: Model and Basic Equationsmentioning

confidence: 99%

“…Recent researches show that anisotropy of the RE sublattice can be larger then the one of the TM sublattice [19]. Therefore, let us investigate how lines of the first and second phase transitions are changed due to the exchange surface anisotropy.…”

Section: Magnetic Phase Diagrammentioning

confidence: 99%

“…At the same time, experiments with TbFeCo with Ta capping layer [18] show that triple loops can appear to the left of the compensation point. To explain this anomalous hysteresis loop, theoretical models [19] were constructed, in which the interplay of the surface anisotropy, and anisotropies of both sublattices led to a modification of the phase diagrams. The thickness and finite size of a ferrimagnetic film can also significantly affect the spin-reorientation transitions and change the phase diagram.…”

Section: Introductionmentioning

confidence: 99%

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Phase transitions in rare-earth ferrimagnets with surface anisotropy near the magnetization compensation point

Yurlov¹,

Zvezdin

Zvezdin³

2021

Preprint

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We report of a theoretical model for calculating the H-T phase diagrams of a rare-earth ferrimagnet, taking into account anisotropies originated by both magnetization sublattices' and by the surface. The possibility of an exchange spring formation due to surface anisotropy is considered. This situation is realized in heterostructures containing a ferrimagnet and a heavy metal. We derive the stability lose lines of the collinear phase from the free energy of the two sublattice ferrimagnet. We numerical calculate the magnetic phase diagrams for the cases when the magnetic field applied along and perpendecular to the easy axis. We demonstrate that tricritical point down at the low field range due to surface anisotropy effect. Moreover, the line of the first order phase transition between angular and collinear phases reduces due to surface anisotropy. In the case when magnetic field is applied perpendicular to the easy axis we show the possibility of the first order phase transition between two collinear phases in contrast to the phase diagram without surface anisotropy.

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“…Very rich and interesting magnetization dynamics [13,14], in terms of fundamental and applied * zvezdin.ka@phystech.edu physics, is observed in these materials near the points of compensation of magnetization and angular momentum. Moreover, by manipulating the temperature of the ferrimagnet near the compensation points, outstanding magnetization switching characteristics can be obtained [15][16][17]. It has been shown that the electrical current can be an efficient approach to magnetization switching [18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Domain wall dynamics of ferrimagnets induced by spin-current near the angular momentum compensation temperature

Yurlov,

Zvezdin,

Skirdkov

et al. 2021

Preprint

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We report on a theoretical study of the spin-current excited dynamics of domain walls (DWs) in ferrimagnets in the vicinity of the angular momentum compensation point. Effective Lagrangian and nonlinear dynamic equations are derived for a two-sublattice ferrimagnet taking into account both spin-torques and external magnetic field. The dynamics of the DW before and after the Walker breakdown is calculated for any direction of the spin current polarization. It is shown that for the in-plane polarization of the spin current, the DW mobility reaches a maximum near the temperature of the angular momentum compensation. For the out-of-plane spin polarization, in contrast, a spin current with the densities below the Walker breakdown does not excite the dynamics of the DW. After overcoming the Walker breakdown, the domain wall velocity increases linearly with increasing the current density. In this spin-current polarization configuration the possibility of a gigahertz oscillation dynamics of the quasi-antiferromagnetic vector under the action of a damping-like torque in the angular momentum compensation point is demonstrated. Possible structures for experimental demonstration of the considered effects are discussed.

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H−T phase diagram of rare-earth–transition-metal alloys in the vicinity of the compensation point

Cited by 25 publications

References 41 publications

Unusual Field Dependence of the Anomalous Hall Effect in Ta/Tb−Fe−Co

Unusual Field Dependence of the Anomalous Hall Effect in Ta/Tb−Fe−Co

Phase transitions in rare-earth ferrimagnets with surface anisotropy near the magnetization compensation point

Domain wall dynamics of ferrimagnets induced by spin-current near the angular momentum compensation temperature

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