Molecular beam epitaxial growth and magneto-transport properties of Mn4−xInxN films on SrTiO3(001) and MgO(001) substrates

Abstract

Ferrimagnetic Mn4N films have a small saturation magnetization with perpendicular magnetic anisotropy (PMA) and are thereby considered suitable materials for ultrafast current-induced domain wall motion (CIDWM). We recently achieved ultrafast CIDWM, reaching 3,000 m/s at room temperature, in compensated ferrimagnet Mn4−xNixN (x = 0.2) films on SrTiO3[STO](001) substrates. In this work, we grew nonmagnetic element In-doped Mn4N epitaxial films (Mn4−xInxN) on two different substrates, STO(001) and MgO(001), by molecular beam epitaxy. The epitaxial growth of these Mn4−xInxN films was demonstrated up to x = 1.40 for those on MgO(001), but limited only to x = 0.12 for those on STO(001). The PMA vanished for greater amounts of In for both substrates. We attribute such a large difference in x between the two substrates to the difference in lattice mismatch between Mn4−xInxN/STO(001) and Mn4−xInxN/MgO(001). We also investigated anomalous Hall effect of the Mn4-xInxN epitaxial films, and discussed their anomalous Hall angles and coercive fields dependence on x.