THICKNESS DEPENDENT ANISOTROPIES IN ULTRATHIN AMORPHOUS CO80B20/AG MULTILAYER FILMS

Ferromagnetic resonance (FMR) was used to study the anisotropies present in Co80B20/Ag multilayer films. The magnetic surface anisotropy constant K(S) was observed to have a constant negative value (favouring an in-plane orientation of the magnetization) for a Co80B20 layer thickness 2L > 20 angstrom, but then to decrease in magnitude for 2L < 20 angstrom. We propose that this behaviour can be accounted for by a magnetostrictive surface anisotropy mechanism. A large deposition induced in-plane volume anisotropy was also observed.