Microstructural control and tuning of thermal conductivity in La0.67Ca0.33MnO3+/-\delta

TL;DR

This study investigates how microstructural factors like density, grain size, and silver impregnation affect the thermal conductivity of La0.67Ca0.33MnO3+/-δ, a material relevant for magnetic refrigeration, demonstrating a threefold increase with silver.

Contribution

It provides new insights into controlling thermal conductivity in manganites through microstructural modifications and silver impregnation.

Findings

Thermal conductivity depends on density, grain size, and silver impregnation.

Silver impregnation increases thermal conductivity threefold.

A simple effective medium model explains the observed trends.

Abstract

Manganites are one of only a small number of material families currently being trialled as room temperature magnetic refrigerants. Here we examine the dependence of the thermal conductivity, K, of La0.67Ca0.33MnO3+/-{\delta} as a function of density, grain size and silver impregnation around room temperature. We use a simple effective medium model to extract relevant trends in the data and demonstrate a threefold increase in thermal conductivity by silver impregnation.