PHENOMENOLOGICAL APPROACH TO THE DEPENDENCE OF MAGNETIC-ANISOTROPY ONCO LAYER THICKNESS IN EPITAXIAL AU CO AND AU/CO/AG SUPERLATTICES/

Co-layer-thickness (t) dependences of magnetic anisotropy energies (K- eff) in epitaxial (111)Au/Co and (111)Au/Co/Ag superlattices are inter preted phenomenologically. Saturation of K-eff at small t in a t - K-e ff plot is attributed to two nonidentical interfaces of each Co layer and the gradient of Co-layer in-plane strain in the thickness directio n. The strains are estimated from the results of in situ reflection hi gh-energy electron diffractometry, which were reported earlier, taking electron penetration to the near-surface regions into account. The ma gnetoelastic interface anisotropy contributing to the perpendicular ma gnetic anisotropy is suggested to arise from a larger magnetoelastic c onstant than that in bulk Co, which is in agreement with recent theore tical calculations.