Persistent spin current in mesoscopic ferrimagnetic spin ring

TL;DR

This paper investigates persistent spin currents in mesoscopic ferrimagnetic rings, revealing quantum fluctuation effects at zero temperature and temperature-dependent behaviors at finite temperatures, with potential implications for spintronics.

Contribution

It introduces a semiclassical approach to analyze persistent spin currents in ferrimagnetic rings, highlighting temperature-dependent behaviors and quantum fluctuation effects.

Findings

Persistent spin current exists at zero temperature due to magnon quantum fluctuations.

At low temperature, the spin current exhibits activation behavior caused by a field-induced gap.

At higher temperatures, the spin current magnitude is proportional to temperature T.

Abstract

Using a semiclassical approach, we study the persistent magnetization current of a mesoscopic ferrimagnetic ring in a nonuniform magnetic field. At zero temperature, there exists persistent spin current because of the quantum fluctuation of magnons, similar to the case of an antiferromagnetic spin ring. At low temperature, the current shows activation behavior because of the field-induced gap. At higher temperature, the magnitude of the spin current is proportional to temperature T, similar to the reported result of a ferromagnetic spin ring.