Magnetic properties of granular films for the composite system (permalloy/Al2O3)

Abstract For the system (permalloy/alumina), granular films prepared by rf co-sputtering have been studied through SQUID magnetization measurements. A decrease of the blocking temperature with the measuring field is found, the variation of which is in agreement with theory. The particle anisotropy is dominated by the shape anisotropy and a surface-induced one.