Superconductivity provides a giant enhancement to the spin battery effect

TL;DR

This paper presents a theoretical model showing that superconductivity significantly amplifies the spin battery effect in superconductor/ferromagnetic insulator systems, explaining recent experimental observations and proposing new detection schemes.

Contribution

It introduces a theory incorporating magnetic proximity effects to explain giant spin accumulation and proposes a non-local detection method for enhanced magnon sensing.

Findings

Superconductivity enhances spin accumulation by several orders of magnitude.

The theory explains the giant inverse spin Hall effect observed experimentally.

A new non-local detection scheme can potentially detect single magnons.

Abstract

We develop a theory of the spin battery effect in superconductor/ferromagnetic insulator (SC/FI) systems taking into account the magnetic proximity effect. We demonstrate that the spin-energy mixing enabled by the superconductivity leads to the enhancement of spin accumulation by several orders of magnitude relative to the normal state. This finding can explain the recently observed giant inverse spin Hall effect generated by thermal magnons in the SC/FI system. We suggest a non-local electrical detection scheme which can directly probe the spin accumulation driven by the magnetization dynamics. We predict a giant Seebeck effect converting the magnon temperature bias into the non-local voltage signal. We also show how this can be used to enhance the sensitivity of magnon detection even up to the single-magnon level.