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

The results of theoretical calculations and experimental data for the effective magnetic anisotropy K-eff (obtained from ferromagnetic resonance measurements) of [Co(8 angstrom)/Cu(d(Cu))](20) (d(Cu)=7-22 angstrom) superlattices with a coherent interaction of the Co and Cu layers prepared by magnetron sputtering are presented. The experimental values of K-eff are an oscillatory function of the thickness d(Cu) interlayers. The computed and experimentally measured dependences K-eff(d(Cu)) are qualitatively similar; stable growth of the parameter K-eff 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 K-eff are discussed; the main one is the oscillatory behavior of the roughness of the interfaces of the layers with increasing d(Cu), resulting in synchronous oscillations of K-eff, resistivity, magnetoresistance, and the ferromagnetic resonance linewidth. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3266917]