In-plane magnetic structure and exchange interactions in the high-temperature antiferromagnet Cr2Al

TL;DR

This study investigates the in-plane magnetic structure and exchange interactions of Cr₂Al, a high-temperature antiferromagnet with potential for spintronics, through experimental synthesis, neutron diffraction, and computational simulations.

Contribution

It provides the first detailed analysis of Cr₂Al's magnetic properties, confirming its in-plane antiferromagnetic order and high Nel temperature, expanding the material options for spintronic applications.

Findings

Cr₂Al has an in-plane magnetic order similar to Mn₂Au.

The Nel temperature of Cr₂Al is approximately 634 K.

First-principles and Monte Carlo simulations agree with experimental results.

Abstract

The ordered tetragonal intermetallic Cr$_2$Al forms the same structure type as Mn$_2$Au, and the latter has been heavily investigated for its potential in antiferromagnetic spintronics due to its degenerate in-plane N\'{e}el vector. We present the single crystal flux growth of Cr$_2$Al and orientation-dependent magnetic properties. Powder neutron diffraction of Cr$_2$Al and first-principles simulations reveal that the magnetic ordering is likely in-plane and therefore identical to Mn$_2$Au, providing a second material candidate in the MoSi$_2$ structure type to evaluate the fundamental interactions that govern spintronic effects. The single ordering transition seen in thermal analysis and resistivity indicates that no canting of the moments along the $c$ axis is likely. Magnetometry, resistivity, and differential scanning calorimetry measurements confirm the N\'{e}el temperature to be $634 \pm 2$ K. First-principles simulations indicate that the system has a small density of states at the Fermi energy and confirm the lowest-energy magnetic ground state ordering, while Monte Carlo simulations match the experimental N\'{e}el temperature.