Quantum-Classical Escape-Rate Transition of a Biaxial Spin System with a Longitudinal Field: a Perturbative Approach

Дата и время публикации : 1998-08-04T14:56:18Z

Авторы публикации и институты :
D. A. Garanin
E. M. Chudnovsky

Ссылка на журнал-издание: Phys. Rev. B 59, 3671 (1999)
Коментарии к cтатье: 4 PR pages, 5 figures, submitted to PRB
Первичная категория: cond-mat.stat-mech

Все категории : cond-mat.stat-mech

Краткий обзор статьи: The quantum-classical transition of the escape rate of the spin model cal H= -DS_z^2 – H_zS_z + B S_x^2 is investigated by a perturbative approach with respect to B [D. A. Garanin, J. Phys A {bf 24}, L61 (1991)]. The transition is first order for B<B_c(H_z), the boundary line going to zero as B_c/D ~ 1 – H_z/(2SD) in the strongly biased limit. The range of the first-order transition is thus larger than for the model cal H = -DS_z^2 – H_zS_z – H_x S_x studied earlier, where in the strongly biased case H_{xc}/(2SD) ~ [1-H_z/(2SD)]^{3/2}. The temperature of the quantum-classical transition, T_0, behaves linearly in the strongly biased case for both models: T_0 ~ 2SD – H_z.

Category: Physics