Perpendicular magnetic anisotropy and magneto-optical Kerr effect of MnSbAg alloy films with NiAs structure

Crystal structures and magneto-optical properties of (MnSb)_100-yAg_y (2.1⩽y⩽10.3) alloy films prepared by RF magnetron sputtering have by been studied by a X-ray diffractometer, a vibrating sample magnetometer and a Kerr loop tracer. The crystal structure of the Mn_47.4Sb_47.5Ag_5.1 alloy film annealed at 300°C is a NiAs-type with HCP. The c-axis orientation is normal to the film plane by annealing at 300°C for 7 hours. The saturation magnetization of the films shows the maximum at y=5.1 and decreases with the increase of y. The perpendicular anisotropy constants of the film annealed at 300°C for 7 hours are K₁=8.7×10⁴ erg/cm³ and K₂=4.9×10⁵ erg/cm³. The Kerr rotation angle of the film decreases with decreasing incident wavelength within the range of 700⩽λ⩽1000 nm. The polar Kerr rotation angles of 0.2° (λ=700 nm) and 0.97° (λ=1000 nm) have been obtained from the film annealed at 300°C for 7 hours