Epitaxial D019-Mn3Ga thin films grown on the paramagnetic and diamagnetic MgO (111) substrate

• Epitaxial growth of MgO (111)/D0 19 -Mn 3 Ga thin films by magnetron sputtering. • Growth at different temperatures modifies structural and magnetic properties. • Magnetic moment attributed to structural defects and D0 22 crystallites. • Subtraction of substrate contributions to magnetic measurements. • MgO substrate behaves simultaneously as paramagnetic and diamagnetic. 50 nm-thick D0 19 -Mn 3 Ga epitaxial thin films were grown on MgO (111) substrates by rf-magnetron sputtering. Structural characterization demonstrated the single crystalline nature of the films grown at 400 and 500 °C, while those grown at 600 °C show an epitaxial mosaic-like growth together with the crystallization of the tetragonal D0 22 phase. The magnetic measurements evidenced the presence of diamagnetic and paramagnetic contributions due to the substrate, with the paramagnetic contribution probably due to magnetic impurities with concentration below 1 % atomic. We removed those contributions in both the magnetization-magnetic field and magnetization-temperature curves. After that correction, the magnetic loops of the D0 19 -Mn 3 Ga thin films were decomposed in antiferromagnetic and ferromagnetic components, employing the Brillouin function, the latest arising from the canting of the magnetic moment of the Mn and the distortion of the kagome spin structure, of the D0 19 phase, at the boundaries between single crystalline domains as well as the ferrimagnetic contribution of the D0 22 clusters.