Swift heavy ion irradiation induced effects in Fe/MgO/Fe/Co multilayer

Abstract

Swift heavy ion irradiation induced effects on magnetic multilayer were investigated on Fe/MgO/Fe/Co multilayer stack grown on Si substrate using e-beam evaporation. This stack was irradiated perpendicularly by 120 MeV Ag15 + with different fluences ranging from 1 × 1011 to 1 × 1013 ions/cm2. X-ray diffraction and transmission electron microscopy infer atomic transportation during irradiation. Magnetic measurements carried out on pristine and irradiated stacks show significant changes in the shape of perpendicular magnetic hysteresis, which envisages the re-orientation of magnetic moment along the direction of ion path. X-ray absorption spectroscopic measurements show the onset of changes in the Fe valence state and O (2p)-metal (3d) hybridization after ion irradiation. The change of valence state predicts the oxide formation at interface, which causes the enhancement of in-plane squareness.