Anomalous Nernst effect in Mn$_3$NiN thin films

TL;DR

This paper reports the first detailed measurement of the anomalous Nernst effect in antiferromagnetic Mn$_3$NiN thin films, revealing insights into their electronic and magnetic properties through combined experimental and modeling approaches.

Contribution

It introduces a reliable experimental method to quantify the anomalous Nernst coefficient in antiferromagnetic antiperovskite thin films, linking it to the anomalous Hall effect.

Findings

Quantified the anomalous Nernst coefficient and conductivity in Mn$_3$NiN.

Established a direct comparison between anomalous Hall and Nernst effects.

Validated experimental results with finite element modeling.

Abstract

The observation of a sizable anomalous Hall effect in magnetic materials with vanishing magnetization has renewed interest in understanding and engineering this phenomenon. Antiferromagnetic antiperovskites are one of emerging material classes that exhibit a variety of interesting properties owing to a complex electronic band structure and magnetic ordering. Reports on the anomalous Nernst effect and its magnitude in this class of materials are, however, very limited. This scarcity may be partly due to the experimental difficulty of reliably quantifying the anomalous Nernst coefficient. Here, we report experiments on the anomalous Nernst effect in antiferromagnetic antiperovskite Mn$_3$NiN thin films. Measurement of both the anomalous Hall and Nernst effects using the same sample and measurement geometry makes it possible to directly compare these two effects and quantify the anomalous Nernst coefficient and conductivity in Mn$_3$NiN. We carefully evaluate the spatial distribution of the thermal gradient in the sample and use finite element modeling to corroborate our experimental results.