MAGNETIC AND MAGNETO-OPTIC PROPERTIES OF TERNARY Co/Pt/Ni/Pt MULTILAYERS

Abstract

Co/Pt/Ni/Pt/ multilayers have been prepared by rf sputtering to study the effect of Ni layer thickness on the magnetic and magneto-optical properties. The magnetization and the Faraday rotation have been interpreted in terms of the properties of Ni layers in Ni/Pt and a good agreement is obtained. The squareness of the loop of Co 5 A/Pt 15 A increases form 0.7 to 1.0 with the addition of very thin Ni layers (≤ 5 A). For Ni layers thinner than about 10 A, the effective anisotropy increases due to the contributions from the surface anisotropy in thin Ni layers and the reduction in 2πM2. For thicker Ni layers this surface anisotropy is negligible and hence the loop shows in-plane character. In Ni/Pt multilayers, Ni layers thinner than 10A are non magnetic at room temperature, but in the present system exchange coupling from Co layers lead to an relative increase in the Curie temperature.