# Spin Seebeck effect in paramagnets and antiferromagnets at elevated temperatures

## TL;DR

This paper develops a unified theoretical framework for the spin Seebeck effect in paramagnets and antiferromagnets at high temperatures, revealing a common proportionality to magnetic field and susceptibility, and predicting a cusp at the Neel temperature.

## Contribution

It introduces a dissipative stochastic model to describe the SSE in paramagnets and antiferromagnets at elevated temperatures, unifying their descriptions.

## Key findings

- SSE signal is proportional to magnetic field and spin susceptibility.
- Predicts a cusp in SSE at the Neel temperature.
- Unified equation for paramagnetic and antiferromagnetic SSE.

## Abstract

We develop a theory of the spin Seebeck effect (SSE) in paramagnets as well as in antiferromagnets at elevated temperatures where the classical limit of the fluctuation-dissipation theorem is applicable. Employing dissipative stochastic models that are valid at these temperatures, we calculate the SSE signal, and we find that both the paramagnetic SSE and the antiferromagnetic SSE are expressed by a single equation that is proportional to the external magnetic field times the spin susceptibility of the magnet. The present result suggests the appearance of a cusp structure at the Neel temperature in the antiferromagnetic SSE signal.