Spin pumping as a generic probe for linear spin fluctuations: demonstration with ferromagnetic and antiferromagnetic orders, metallic and insulating electrical states

TL;DR

This study demonstrates that spin pumping can serve as a universal probe for detecting linear spin fluctuations across various magnetic orders and electronic states, enhancing material characterization in spintronics.

Contribution

It introduces a systematic experimental method using spin pumping to detect spin fluctuations, applicable to both metallic and insulating magnetic materials.

Findings

Enhanced spin pumping correlates with magnetic ordering transitions.

The effect is independent of the material's metallic or insulating nature.

Spin fluctuations can be effectively probed via electronic or magnonic transport.

Abstract

We investigated spin injection by spin pumping from a spin-injector(NiFe) into a spin-sink to detect spin fluctuations in the spin-sink. By scanning the ordering-temperature of several magnetic transitions, we found that enhanced spin pumping due to spin fluctuations applies with several ordering states: ferromagnetic(Tb) and antiferromagnetic(NiO, NiFeOx, BiFeO3, exchange-biased and unbiased IrMn). Results also represent systematic experimental investigation supporting that the effect is independent of the metallic and insulating nature of the spin-sink, and is observed whether the spin current probe involves electronic or magnonic transport, facilitating advances in material characterization and engineering for spintronic applications.