Anomalous Behavior of Magnetization and Perpendicular Magnetic Anisotropy for Heusler Compound Type Multilayer Films, PtMnSb/CuMnSb

Multilayer films consisting of ferromagnetic PtMnSb and antiferromagnetic CuMnSb were prepared by a dual-type rf sputtering method. The thickness of a PtMnSb layer (dPt) was designed from 3.6 Å to 100 Å, holding the CuMnSb layer thickness constant at 100 Å. From X-ray diffraction data, all multilayer films were found to have a [111] texture of the C1b-type Heusler structure. The magnetization of multilayer films showed anomalous behavior: 1) a great enhancement of the magnetization compared with that of a PtMnSb compound; and 2) a bend in the temperature dependence of the magnetization at about 50 K, near the Néel temperature of CuMnSb. The magnetization curve revealed that a perpendicular magnetic anisotropy was induced with decreasing dPt. The interface contribution (Ks) and the volume contribution (Kv) to the perpendicular magnetic anisotropy were estimated to be Ks = 0.14 erg/cm2 and Kv = -7.9 x 10(6) erg/cm3.