Structural and Magnetotransport Properties of Epitaxial Ferrimagnetic Mn₄N Thin Films on GaN by Plasma-assisted Molecular Beam Epitaxy

The III-nitride family of wide bandgap semiconductors are of great importance for diverse applications ranging from solid-state lighting to RF and power electronics (D. Jena, Jpn. J. Appl. Phys. 58, SC0801 (2019)). Integration of ferromagnets on GaN will be important building block not only for device applications aiming to merge logic, memory and communication components but also for studying spin-related phenomena in non-centrosymmetric semiconductors.
Mn4N, a room temperature metallic nitride ferrimagnet is of high interest for applications exploiting spin torques, due to its large spin polarization, strong perpendicular magnetic anisotropy, low saturation magnetization and high domain wall velocities (T. Gushi, Nano Lett. 19, 8716 (2019)).
Here we report integration of Mn₄N on GaN with smooth surface by plasma assisted molecular beam epitaxy. The structural and magnetic properties of Mn₄N on GaN, including growth mode, lattice spacing, surface morphology, Hall resistance are tailored by varying the growth parameters. Square hysteresis loops with large remanence (>90%) and moderate coercive field (~0.5T) are achieved.