Microstructures and magnetic properties of the FIB irradiated co-pd multilayer films

The effects of Ga-ion irradiation on a microstructure, layered structure, and magnetic properties of Co-Pd multilayers are investigated. A decrease of the diffraction peak in low angle X-ray diffraction showed that the regular interface between Co and Pd layers was blurred by ion irradiation. The ion irradiation changed the easy axis of magnetization from perpendicular to an in-plane direction at an ion dose of 5×10¹⁴ and 5×10¹⁵ ions/cm² for Co-Pd₆ and Co-Pd₂₀ multilayers, respectively. Magnetic force microscopy images of irradiated films showed that the magnetic contrast significantly decreased with increasing ion dose, which corresponds to a decrease of the perpendicular magnetic anisotropy.