Calculation of Spin Tunneling Effects in the Presence of an Applied Magnetic Field

TL;DR

This paper presents a straightforward quantum mechanical approach to calculate spin tunneling effects in ferromagnetic particles under magnetic fields, clarifying the influence of potential asymmetry and aiding experimental detection.

Contribution

It introduces a simple Schroedinger theory-based method for calculating energy level splitting due to spin tunneling, extending previous path integral results to excited states.

Findings

Derived the tunneling splitting for excited states.

Clarified the role of barrier asymmetry.

Provided a practical method for experimental analysis.

Abstract

The tunneling splitting of the energy levels of a ferromagnetic particle in the presence of an applied magnetic field - previously derived only for the ground state with the path integral method - is obtained in a simple way from Schroedinger theory. The origin of the factors entering the result is clearly understood, in particular the effect of the asymmetry of the barriers of the potential. The method should appeal particularly to experimentalists searching for evidence of macroscopic spin tunneling.