Anomalous Nernst effect in the noncollinear antiferromagnet Mn$_5$Si$_3$

TL;DR

This study reports the observation of the anomalous Nernst effect in Mn$_5$Si$_3$, revealing how complex magnetic phase transitions influence electronic transport properties in noncollinear antiferromagnets.

Contribution

It provides the first measurement of the anomalous Nernst effect in Mn$_5$Si$_3$, linking magnetic phase changes to thermoelectric responses in this material.

Findings

Sign change of Nernst signal below 25 K

Correlation between Nernst effect and magnetic phase transition

Reduction of Hall signal and magnetization at low temperatures

Abstract

Investigating the off-diagonal components of the conductivity and thermoelectric tensor of materials hosting complex antiferromagnetic structures has become a viable method to reveal the effects of topology and chirality on the electronic transport in these systems. In this respect, Mn$_5$Si$_3$ is an interesting metallic compound that exhibits several antiferromagnetic phases below 100 K with different collinear and noncollinear arrangements of Mn magnetic moments. Previous investigations have shown that the transitions between the various phases give rise to large changes of the anomalous Hall effect. Here, we report measurements of the anomalous Nernst effect of Mn$_5$Si$_3$ single crystals. Below 25 K we observe a sign change of the zero-field Nernst signal with a concomitant decrease of the Hall signal and a gradual reduction of the remanent magnetization which we attribute to a subtle rearrangement of the magnetic moment configuration at low temperatures.