Effect of Inserted Carbon Layer on Coercivity of L1₀-FePt/Fe Exchange Coupled Composite Films

The exchange coupled composite L1₀-FePt/Fe/C_n thin films, with carbon-layers inserted, were synthesized by magnetron co-sputtering and by post-annealing on the Ag pre-coated glass substrates. The influence of the thickness of inserted carbon layer on coercivity of L1₀-FePt/Fe/C_n multi-layers was experimentally investigated. The results show that C-layer thickness of the thin films significantly affected the coercivity. For example, with a fixed number ofFe/C_n nano-period, as the C-layer thickness increased, the coercivity changed in a decrease-increase mode, being minimized with a C-layer thickness of 1 nm. In addition, the optimized thickness of the carbon layer, inserted into the self-designedL1₀-FePt/C_n/Fe (5 nm) multilayers, not only decreased the coercivity but also improved the intergranular interaction and enhanced the signal-to-noise ratio.