Flattop-Type Writer Using Soft Magnetic Films with High Resistivity

Abstract

To improve write performance at high frequency, a flattop-type head consisting of a flat upper yoke and sputtered soft magnetic films is proposed. The sputteredFeAlO films used as yoke materials are magnetically soft, and have a resistivityρ of -100 μΩcm, a saturation magnetic flux density B_s of -1.8T, and an anisotropy field H_k of -25 Oe. All of these values for the FeAlO films are higher than those of conventional plated NiFe yoke materials. The yoke thickness and length are 2μm and 18μm, respectively. A flattop-type head containing an FeAlO yoke at a high writing frequency of more than 540 Mfrps has an O/W of around -30 dB and shows good NLTS (≤15%). Consequently, the improvement of the write performance at high frequency is confirmed when plated 45-50 NiFe films are replaced by sputtered FeAlO films as yoke materials.