Magnetic Properties and Kerr Effects in PtMnSb Thin Films

Dependence of magnetic properties and Kerr effects in PtMnSb thin films on oxygen partial pressure during annealing was investigated. The coercivity Hc¿ increased with oxygen partial pressure, while the change in Hc¿ was relatively small. The saturation magnetization Ms was almost constant up to 6 × 10^¿4 Torr, and then decreased rapidly at higher O2 pressures. The Kerr rotation angle in zero magnetic field ¿K(0) and the squareness ratio Rs of Kerr loops took on maximum values at or near 8 × 10^¿4 Torr of 0.85° and 0.45 respectively. SEM observations and X-ray diffraction studies revealed that these values are related to the preferential oxidation at PtMnSb columnar boundaries. The oxidation may shorten the size of columns and isolate them from each other.