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

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.