Quantum spin tunneling of magnetization in small ferromagnetic particles

TL;DR

This paper introduces a quantum approach to describe magnetization tunneling in small ferromagnetic particles, providing estimates for critical magnetic fields and tunneling factors, and identifying the temperature where quantum effects dominate.

Contribution

It presents a novel quantum method for analyzing magnetization tunneling in small ferromagnetic particles, including analytic expressions and estimates for key parameters.

Findings

Estimated saturation magnetic field along the easy axis.

Derived an analytic expression for the tunneling factor without external field.

Identified the crossover temperature where quantum tunneling dominates.

Abstract

A new quantum approach is presented that can account for the description of small ferromagnetic particles magnetization tunneling. An estimate of the saturation value of an external applied magnetic field along the easy axis is obtained. An analytic expression for the tunneling factor in the absence of an external magnetic field is deduced from the present approach that also allows to obtain the crossover temperature characterizing the regime where tunneling is dominated by the quantum effects.