Tuning the ferromagnetism of epitaxial-strained D019-Mn3Ga thin films

The hexagonal D019-Mn3Ga phase is a non-collinear antiferromagnet with a triangular spin configuration. The Mn magnetic moments, lying in the (0 0 1) basal plane, are slightly canted towards the c axis producing a ferromagnetic component (FMC), which saturation magnetization in bulk samples is 7.7 kAm−1. Here, we report on the epitaxial growth of Mn3Ga epitaxial thin films on MgO(1 1 1), GaN(0 0 1) and MgO(0 0 1)/Pt(1 1 1) substrates with lattices mismatches of −4.77%, 2.1%, and 2.45%, respectively. Structural characterization with reflection high-energy electron diffraction was used to evaluate the critical thicknesses at which relaxation is reached. We provide evidence of the manipulation of the magnitude of the FMC of the Mn3Ga thin films grown under tensile and compressive deformations. The FMC has been tuned from 23.7 to 11.8 and 2.5 kAm−1 for the growth of Mn3Ga on MgO(1 1 1), GaN(0 0 1), and MgO(0 0 1)/Pt(1 1 1) substrates. The modulation of the FMC is explained in terms of the Dzyaloshinskii-Moriya interaction.