Optimization of high Bsat FeCo films for write pole applications

FeCo films and their lamination with ultrathin NiFe layers down to 5Å were deposited using dc magnetron sputtering techniques. Soft magnetic FeCo films were obtained at an optimal target power of 500W and an optimal deposition pressure of 2mTorr with high saturation flux density, Bsat>2.4T, and low easy-axis coercivity, Hce⩽15Oe, and hard-axis coercivity, Hch⩽3Oe, at a film thickness of 2000Å. While the magnetostriction remains at ∼4×10−6 the stress was further optimized by applying substrate bias at a controlled level ⩽50V without sacrificing film magnetic softness.