Induced anisotropy in soft magnetic Fe65Co35/Co thin films

Two methods to control the magnetic anisotropy were developed in magnetically soft FeCo (=Fe65Co35) sputtered films with a thin Co underlayer. One method was to deposit the FeCo/Co films by varying the substrate–target spacing dT–S. It changed the energy and incident angle of Fe(Co) atoms arriving at the substrate and influenced the film growth and microstructure. The magnetic anisotropy three times larger than that of film deposited at normal dT–S was observed. The other method was to deposit the films on a series of prestressed glass substrates. An anisotropic stress with different amplitudes was systematically introduced into the films when the prestressed substrate was released. It was found that the magnetic anisotropy was strongly affected by the amplitude and direction of applied stress. An Hk of 250 Oe (=19.9 kA/m) was induced in the film without deteriorating the soft magnetic properties.