Magnetic anisotropy of Co∕Cu (111) superlattices: calculation and experiment

Abstract

The results of theoretical calculations and experimental data for the effective magnetic anisotropy Keff (obtained from ferromagnetic resonance measurements) of [Co(8Å)∕Cu(dCu)]20 (dCu=7–22Å) superlattices with a coherent interaction of the Co and Cu layers prepared by magnetron sputtering are presented. The experimental values of Keff are an oscillatory function of the thickness dCu interlayers. The computed and experimentally measured dependences Keff(dCu) are qualitatively similar; stable growth of the parameter Keff with increasing thickness of the nonmagnetic layers is observed (against the background of oscillations of the experimental curve), which is a direct consequence of the growth of axial distortions of the initial cubic structure of cobalt under the conditions of pseudomorphism. The reasons for the appearance of oscillations of Keff are discussed; the main one is the oscillatory behavior of the roughness of the interfaces of the layers with increasing dCu, resulting in synchronous oscillations of Keff, resistivity, magnetoresistance, and the ferromagnetic resonance linewidth.