Structural, magnetic, and electrical properties of collinear antiferromagnetic heteroepitaxy cubic Mn${}_3$Ga thin films

Abstract

Although a cubic phase of Mn${}_3$Ga with an antiferromagnetic order has been theoretically predicted, it has not been experimentally verified in a bulk or film form. Here, we report the structural, magnetic, and electrical properties of antiferromagnetic cubic Mn${}_3$Ga (C-Mn${}_3$Ga) thin films, in comparison with ferrimagnetic tetragonal Mn${}_3$Ga (T-Mn3Ga). The structural analyses reveal that C-Mn${}_3$Ga is hetero-epitaxially grown on MgO substrate with the Cu${}_3$Au-type cubic structure, which transforms to T-Mn${}_3$Ga as the RF sputtering power increases. The magnetic and magnetotransport data show the antiferromagnetic transition at T${}_N$ = 400 K for C-Mn${}_3$Ga and the ferrimagnetic transition at T${}_C$ = 820 K for T-Mn${}_3$Ga. Furthermore, we find that the antiferromagnetic C-Mn${}_3$Ga exhibits a higher electrical resistivity than the ferrimagnetic T-Mn${}_3$Ga, which can be understood by spin-dependent scattering mechanism.

15 pages, 4 figures