Magneto-elastic coupling in a sinusoidal modulated magnet Cr$_2$GaN

TL;DR

This study investigates the magnetic and crystal structures of Cr$_2$GaN, revealing a sinusoidal incommensurate magnetic order and strong magneto-elastic coupling, with potential for multifunctional applications.

Contribution

It provides the first detailed characterization of the magnetic structure and magneto-elastic coupling in Cr$_2$GaN using neutron diffraction and Rietveld refinement.

Findings

Magnetic phase transition at ~170 K

Incommensurate sinusoidal magnetic structure identified

Strong magneto-elastic coupling observed

Abstract

We use neutron powder diffraction to investigate the magnetic and crystalline structure of Cr$_2$GaN. A magnetic phase transition is identified at $T \approx 170$ K, whereas no trace of structural transition is observed down to 6 K. Combining Rietveld refinement with irreducible representations, the spin configuration of Cr ions in Cr$_2$GaN is depicted as an incommensurate sinusoidal modulated structure characterized by a propagating vector ${k}$=(0.365, 0.365, 0). Upon warming up to the paramagnetic state, the magnetic order parameter closely resembles to the temperature dependence of $c$-axis lattice parameter, suggesting strong magneto-elastic coupling in this compound. Therefore, Cr$_2$GaN provides a potential platform for the exploration of magnetically tuned properties such as magnetoelectric, magnetostrictive and magnetocaloric effects, as well as their applications.