Soft magnetic properties of FeCo films with Co underlayer

Bilayered Fe65Co35 (=FeCo)/Co films were prepared by facing targets sputtering with 4πMs∼24 kg. The soft magnetic properties of FeCo films were induced by a Co underlayer. Hc decreased rapidly when the Co underlayer was 2 nm or more. The films showed well-defined in-plane uniaxial anisotropy with the typical values of Hce=10 Oe and Hch=3 Oe, respectively. High frequency characteristics of the films show the films can work at 0.8 GHz with real permeability as high as 250.