Perpendicular Magnetic Anisotropy of Co-Au Multilayers Induced by Interface Sharpening

Abstract

Co-Au multilayers with Co layer thicknesses between 22 and 5 \AA{}A, prepared by ion-beam sputtering, have an easy-plane magnetic anisotropy. Their saturation magnetization indicates the presence of diffuse interfaces, caused by ion-beam mixing. Annealing of the multilayers at 250-300\ifmmode^\circ\else\textdegree\fi{}C leads to a perpendicular anisotropy for Co thicknesses below about 14 \AA{}A. This effect is attributed to a stronlgy enhanced interface anisotropy, which is due to sharpening of the interfaces as revealed by x-ray diffraction.