Spin-wave propagation and transformation in a thermal gradient

TL;DR

This paper investigates how thermal gradients affect spin-wave propagation in magnetic insulators, revealing wavelength changes and mode decomposition that could enable advanced spin-caloritronic device control.

Contribution

It demonstrates the impact of temperature on spin-wave behavior and introduces a method to manipulate spin waves via thermal gradients in magnetic insulators.

Findings

Waves slow down and change wavelength in colder regions.

Hotter regions cause wave decomposition into different modes.

Thermal effects are mainly due to changes in saturation magnetization.

Abstract

The influence of a thermal gradient on the propagation properties of externally excited dipolar spin waves in a magnetic insulator waveguide is investigated. It is shown that spin waves propagating towards a colder region along the magnetization direction continuously reduce their wavelength. The wavelength increase of a wave propagating into a hotter region was utilized to realize its decomposition in the partial waveguide modes which are reflected at different locations. This influence of temperature on spin-wave properties is mainly caused by a change in the saturation magnetization and yields promising opportunities for the manipulation of spin waves in spin-caloritronic applications.