Anisotropy and magneto-optical studies in evaporated Co/Pt multilayer

Co/Pt multilayer films have been prepared by evaporation under UHV (ultrahigh-vacuum) conditions, and their magnetic and magnetooptical properties were studied. For samples with Co-layer thickness below about 1 nm, rectangular loops are observed with H_c on the order of 1 kOe. For these samples, the uniaxial anisotropy is as high as 1×10⁷ erg cm^-3, and it depends on the relative thicknesses of both Pt and Co. While the polar Kerr rotation decreases with decreasing Co-layer thickness, the Faraday rotation, on the contrary, is seen to increase strongly. This increase has been attributed to the presence of a Co-Pt alloy layer formed by mixing at the interfaces; its thickness has been estimated to be about 0.3 nm. Faraday rotation study is hence a useful tool in characterizing the multilayers. It is suggested that this layer plays an important role in the origin of K_u. It has been found that M and K_u are practically independent of temperature for 5<T<300 K. The T_c is well above 600 K