Thermal conductance of thin film YIG determined using Bayesian statistics

TL;DR

This paper introduces a Bayesian statistical approach combined with 2D heat transport modeling to accurately measure the thermal conductance of thin film YIG, especially in systems where traditional methods fail, providing temperature and magnetic field dependent data.

Contribution

The study develops a novel Bayesian analysis technique integrated with 2D heat transport modeling to evaluate 3-omega measurements in YIG thin films, overcoming limitations of standard methods.

Findings

Thermal conductance data of YIG films from room temperature to 10 K.

Magnetic field effects on thermal conductance between 10 K and 50 K.

Method enables analysis of systems previously inaccessible with conventional 3-omega analysis.

Abstract

Thin film YIG (Y$_3$Fe$_5$O$_{12}$) is a prototypical material for experiments on thermally generated pure spin currents and the spin Seebeck effect. The 3-omega method is an established technique to measure the cross-plane thermal conductance of thin films, but can not be used in YIG/GGG (Ga$_3$Gd$_5$O$_{12}$) systems in its standard form. We use two-dimensional modeling of heat transport and introduce a technique based on Bayesian statistics to evaluate measurement data taken from the 3-omega method. Our analysis method allows us to study materials systems that have not been accessible with the conventionally used 3-omega analysis. Temperature dependent thermal conductance data of thin film YIG are of major importance for experiments in the field of spin-caloritronics. Here we show data between room temperature and 10 K for films covering a wide thickness range as well as the magnetic field effect on the thermal conductance between 10 K and 50 K.