Structural, magnetic, and electrical properties of collinear antiferromagnetic heteroepitaxy cubic Mn3Ga thin films

Abstract

We report the structural, magnetic, and electrical properties of antiferromagnetic cubic Mn3Ga thin films, in comparison with ferrimagnetic tetragonal Mn3Ga. The structural analyses reveal that cubic Mn3Ga is heteroepitaxially grown on a MgO substrate with a disordered Cu3Au-type cubic structure, which transforms to tetragonal Mn3Ga as the RF sputtering power increases. In cubic Mn3Ga, the Mn moments aligned ferromagnetically in layers are stacked antiferromagnetically between layers, compared to the theoretical prediction. The magnetic and magnetotransport data show the antiferromagnetic transition at TN = 400 K for cubic Mn3Ga and the ferrimagnetic transition at TC = 820 K for tetragonal Mn3Ga. Furthermore, we find that the antiferromagnetic cubic Mn3Ga exhibits a higher electrical resistivity than the ferrimagnetic tetragonal Mn3Ga, which can be understood by the spin-dependent scattering mechanism.