Tunneling Rate for Superparamagnetic Particles by the Instanton Method

TL;DR

This paper derives an analytical expression for the tunneling rate of superparamagnetic particles using the instanton method, highlighting the challenges in observing magnetization changes due to large spin values.

Contribution

It introduces a path integral approach to analytically calculate tunneling rates for large-spin paramagnetic molecules, advancing theoretical understanding.

Findings

Analytical expression for tunneling rate derived

Large spins (~3000 hbar) make magnetization change observation unlikely

Path integral method applied to collective spin model

Abstract

We derive the tunneling rate for paramagnetic molecules in the context of a collective spin model. By means of path integral methods an analytical expression is derived. Given the very large spins in question (s ~ 3000 hbar), the observation of magnetization changes due to pure unitary tunnel effects is unlikely.