MAGNETIC-PROPERTIES AND STRUCTURE OF MN4N FILMS ON GLASS SUBSTRATES

Ferrimagnetic Mn4N films were deposited in situ on glass substrates, b y d.c. reactive magnetron sputtering from a sintered Mn target. An Mn4 N ordered structure was obtained at a substrate temperature of 150-250 degrees C and gas pressure of 3-8 mTorr (flow rate ratio Ar:N-2 = 2:1 ), without any further annealing. Perpendicular magnetic anisotropy ex ists in these films, resulting in a larger coercivity (1150-2300 Oe) m easured perpendicular to the film plane than that parallel (650-1550 O e). The coercivity in either direction decreases with increasing subst rate temperature, while it increases with increasing gas pressure. The saturation flux density of the films is 120-610 G, increasing with in creasing substrate temperatures. The resulting perpendicular magnetic anisotropy is attributed to the ordering in the crystal structure, fro m the stress-induced anisotropy and from the shape anisotropy.