Soft Magnetic Properties of Nonequilibrium bcc Fe–Hf Alloys Produced by rf Sputtering

Abstract

Microstructure and magnetic properties of Fe–rich Fe–Hf alloy films produced by rf sputtering have been investigated as a function of Hf content. The films in the concentration range 1–6 at%Hf have a nonequilibrium bcc phase with fine grains of 5 to 20 nm and exhibit high saturation magnetization and soft magnetic properties. In particular, the bcc Fe_95.6Hf_4.4 film annealed at 673 K for 3.6 ks exhibits a saturation magnetization of 1.9 T and an effective permeability of 1800 at 1 MHz.