Perpendicular magnetic anisotropy of Mn4N films fabricated by reactive sputtering method

Manganese nitride films were fabricated on MgO substrates by changing N-2 flow ratio into Ar gas (P-N2) during reactive sputtering deposition of the films, and their crystal structures and magnetic properties were investigated. Single phased epsilon-Mn4N films were obtained when P-N2 was 5%-9%, and the tetragonal lattice distortion was identified in all the Mn4N films (the lattice constant ratio, c/a = 0.99). Perpendicular magnetic anisotropy was observed in all the specimens. The Mn4N film, fabricated with P-N2 = 8%, has a low saturation magnetization (M-s = 110 emu/cc) and relatively high magnetic anisotropic energy (K-u = 8.8 x 10(5) erg/cc). Both M-s and K-u of the films drastically changed with mixing other phases (alpha-Mn, beta-Mn, eta-Mn3N2, and possibly gamma-Mn) by varying P-N2. (c) 2015 AIP Publishing LLC.