Probing short-range magnetic order in a geometrically frustrated magnet by spin Seebeck effect

TL;DR

This study shows that the spin Seebeck effect can effectively detect short-range magnetic order in geometrically frustrated magnets, revealing field-induced magnetic correlations at very low temperatures.

Contribution

It introduces the use of the spin Seebeck effect as a sensitive probe for short-range magnetic order in frustrated magnets, supported by experimental and theoretical analysis.

Findings

SSE detects modulations indicating short-range magnetic order

Field-induced magnetic ordering is observed at low temperatures

SRO is anisotropic with respect to the applied magnetic field

Abstract

Competing magnetic interactions in geometrically frustrated magnets give rise to new forms of correlated matter, such as spin liquids and spin ices. Characterizing the magnetic structure of these states has been difficult due to the absence of long-range order. Here, we demonstrate that the spin Seebeck effect (SSE) is a sensitive probe of magnetic short-range order (SRO) in geometrically frustrated magnets. In low temperature (2 - 5 K) SSE measurements on a model frustrated magnet \mathrm{Gd_{3}Ga_{5}O_{12}}, we observe modulations in the spin current on top of a smooth background. By comparing to existing neutron diffraction data, we find that these modulations arise from field-induced magnetic ordering that is short-range in nature. The observed SRO is anisotropic with the direction of applied field, which is verified by theoretical calculation.