# Spin pumping and shot noise in ferrimagnets: bridging ferro- and antiferromagnets

## TL;DR

This paper theoretically investigates spin transport and shot noise in ferrimagnets interfaced with non-magnetic conductors, revealing how sublattice asymmetry influences spin current and how shot noise can probe quasiparticle properties.

## Contribution

It introduces a comprehensive spin current expression including intra- and cross-sublattice effects, advancing understanding of spin-pumping in ferrimagnets and the role of interface asymmetry.

## Key findings

- Spin current depends on sublattice asymmetry and interfacial coupling.
- Shot noise can probe quasiparticle spin and interface properties.
- Theoretical framework bridges ferro- and antiferromagnetic spin transport.

## Abstract

A combination of novel technological and fundamental physics prospects has sparked a huge interest in pure spin transport in magnets, starting with ferromagnets and spreading to antiferro- and ferrimagnets. We present a theoretical study of spin transport across a ferrimagnet$|$non-magnetic conductor interface, when a magnetic eigenmode is driven into a coherent state. The obtained spin current expression includes intra- as well as cross-sublattice terms, both of which are essential for a quantitative understanding of spin-pumping. The dc current is found to be sensitive to the asymmetry in interfacial coupling between the two sublattice magnetizations and the mobile electrons, especially for antiferromagnets. We further find that the concomitant shot noise provides a useful tool for probing the quasiparticle spin and interfacial coupling.