Possible Interplay Between Intrinsic and Extrinsic Ferromagnetic Damping Mechanisms

Here we present a ferromagnetic resonance investigation in which we measure the resonance field and linewidth in a series of films that were fabricated by oblique sputtering deposition. From the angular dependence of the resonance field we were able to extract the uniaxial anisotropy field. We show that microstructures that grow in the inclined films, induce very strong uniaxial anisotropy field values that vary from ~0 Oe to around 300 Oe, for deposition angles varying from 0° to 70°. From the angular dependence of the linewidth we were also able to investigate the spin relaxation mechanisms existent in these films. From the measurements it is possible to separate the contributions from intrinsic (Gilbert parameter) and extrinsic (two-magnon) relaxation processes. For films grown at deposition angles between 0° and 40° the Gilbert parameter ¿ value keeps an almost fixed value of 0.011 while the two-magnon contribution is negligible. For films grown at the oblique angle of 40° the Gilbert parameter ¿ abruptly decreases to 0.008 and the two-magnons parameter ¿¿ suddenly jumps to almost 1.0 GHz. For films grown at angles bigger than 40°, ¿ monotonically increases and the two-magnon parameter contribution monotonically decreases.