Thermally assisted macroscopic quantum tunneling of a ferromagnetic particle in a magnetic field at an arbitrary angle

TL;DR

This paper investigates how thermal effects influence quantum tunneling of magnetization in small ferromagnetic particles with biaxial symmetry under arbitrary magnetic field angles, providing numerical and approximate analyses of tunneling rates.

Contribution

It offers a detailed numerical and analytical study of thermally assisted quantum tunneling in ferromagnetic particles at various magnetic field orientations.

Findings

Numerical WKB exponents below the crossover temperature.

Approximate WKB exponent near the crossover region.

Discussion of quantum fluctuations beyond the crossover regime.

Abstract

At finite temperature we study the quantum tunneling of magnetization for a small ferromagnetic particle with the biaxial symmetry placed in a magnetic field at an arbitrary angle. We present numerical WKB exponent below the crossover temperature in which the quantum tunneling is affected by the thermal activation, and the approximate form of the WKB exponent around the crossover region. The effect of quantum fluctuations on the thermal activation rate beyond the crossover regime are discussed.