Carbon Capping Layer Effect on Magnetic Properties and Microstructure of FePt/MoC/CrRu Films

Abstract

A capping C layer with various thicknesses was sputtered on FePt/MoC/CrRu/glass and postannealed from 190°C to 365°C. The optimal magnetic property was obtained at 2 nm-thick C layer annealed at 268°C and used to discuss an FePt thickness effect. The FePt films with a thickness of 4-10 nm were deposited on MoC/CrRu at 425°C using magnetron sputtering. The MoC intermediate layer was epitaxially grown on the (200) textured CrRu seed layer, and the FePt film was prepared on the (200) textured MoC at 425°C. The FePt film shows strong (001) texture, and the out-of-plane coercivity of 7.5 kOe has been demonstrated in 10 nm-thick FePt film. After capping a 2 nm-thick C layer and postannealed at 268°C, the out-of-plane coercivity was increased to 10 kOe compared with FePt without C capping. From microstructure, the FePt grains were distributed in-or between-islandlike structure and further separated by excess carbon from a capping carbon layer and an MoC intermediate layer.