Temperature-dependent magnetic anisotropy from pseudo-dipolar interactions

Article

关键词: WEAK FERROMAGNETISM;    MODEL;    IONS;   

DOI  :  10.1103/PhysRevB.95.184413

来源: SCIE

【 摘 要 】

Magnetic anisotropy of spin models with pseudo-dipolar interactions is theoretically studied in the hightemperature paramagnetic phase. Using the high-temperature expansion, we show that the pseudo-dipolar interaction gives rise to a magnetic anisotropy which shows. proportional to T-5 temperature dependence. This phenomenon arises from the pseudo-dipolar interaction and is distinct from the orbital effect, such as Van Vleck susceptibility. By an explicit calculation, it is shown that the second order in the high-temperature expansion prefers to point the spins along the bond direction. The theory is applied to the Heisenberg-Kitaev model on the honeycomb lattice and a cubic lattice model which is potentially relevant to perovskite oxides. The leading order for the magnetic anisotropy arises from the second order in high-temperature expansion, which contribute to a fourth-order anisotropic term in Landau theory. The result shows that the anisotropy from the pseudo-dipolar interaction gives rise to (100) magnetic anisotropy. These results are potentially relevant to heavy-transition-metal oxides such as iridates. Experimental observation of the magnitude of anisotropic interactions using magnetic torque measurement is also discussed.

【 授权许可】

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