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

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 T_N = 400 K for cubic Mn₃Ga and the ferrimagnetic transition at T_C = 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.