Static and Dynamic Characterizaton of Interfacial Anisotropy in Magnetic Superlattices
We have observed large discrepancies between the DC magnetization and ferromagnetic resonance (FMR) magnetic anisotropy in Mo/Ni superlattices. We show that higher order anisotropy is present in both measurements and develop an analysis by which the first order and second order energies can be treated independently. The low temperature results show a systematic divergence of the first order FMR and DC anisotropy as the Ni layer thickness decreases. It is shown that the source of the divergence is an enhanced surface anisotropy measured by FMR. Possible sources of this enhancement are discussed.