Enhanced Thermoelectric Performance of $p$-type BiSbTe Through Incorporation of Magnetic CrSb

TL;DR

This study demonstrates that adding magnetic CrSb to p-type BiSbTe enhances thermoelectric performance by increasing thermopower and reducing thermal conductivity, achieving a peak zT of 1.4 at 325 K.

Contribution

It introduces a novel approach of incorporating magnetic CrSb into BiSbTe to improve thermoelectric efficiency through magnetic interactions and phase engineering.

Findings

Increased thermopower due to magnetic phase inclusion.

Significant reduction in thermal conductivity.

Achieved peak zT of ~1.4 at 325 K.

Abstract

There is evidence that magnetism can potentially increase the thermopower of materials, most likely due to magnon scattering, suggesting the incorporation of intrinsic magnetic semiconductors in non-magnetic thermoelectric materials. Here, samples of $\textit{p}$-type Bi$_{0.5}$Sb$_{1.5}$Te$_{3}$ with 10 at.% excess Te are ball-milled with varying ratio of the antiferromagnetic semiconductor CrSb (0, 0.125, 0.5, and 1 wt.%) to prepare bulk samples by spark plasma sintering technique. The thermopower of samples containing CrSb is increased due to an increase in the effective mass of the charge carriers, indicating that there is a drag effect originating from the magnetic particles. However, this was at the expense of reduced electrical conductivity caused by reduced charge carrier mobility. While overall only marginal improvements in power factors were observed, these samples exhibited significantly lower thermal conductivity compared to the single-phase material. As a result, a peak $\textit{zT}$ value of $\sim$1.4 was achieved at 325 K for the sample with 0.125 wt.% CrSb. These results highlight the potential of incorporating magnetic secondary phases to enhance the thermoelectric performance of materials.