Uniaxial magnetic anisotropy of Fe-Si and Co-Si amorphous thin films due to Si nano-segregation

Fe-Si and Co-Si amorphous thin films with Si concentrations above their eutectic point were deposited by magnetron sputtering. The films had a well defined uniaxial magnetic anisotropy induced by evaporating the Si atoms at an oblique angle of incidence. Their anisotropy energy and coercive field, measured by the transverse Kerr effect, increased with the temperature, suggesting that the distribution of Si concentration was not homogeneous giving rise to regions with different Curie temperatures. A model was proposed where the anisotropic distribution of Si would explain the origin of the uniaxial magnetic anisotropy in these films and the anomalous behaviour of their anisotropy energy and coercivity with the temperature. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.