A thin film head for high density magnetic recording using CoZr amorphous films

Abstract

A thin film head using CoZr amorphous films has been developed for high density magnetic recording. The head has a single‐layered 17‐turn spiral copper coil, 0.2‐μm head gap length, 15‐μm track width, and 2‐μm‐thick CoZr films on an IBM 3370 type slider. The copper coil was electroplated through a photoresist pattern, which was fabricated by the oxygen ion milling to obtain a high aspect ratio (1.5 μm width, 3.4 μm thickness, 3.5 μm space). CoZr films used here have excellent magnetic properties, such as low coercive force (H_c≤0.05 Oe), high permeability ( μ≂3500 at 10 MHz), and high saturation magnetization (4πM_s ≂14 000 G). These heads were evaluated using 8‐in. Co‐Ni‐P plated disks which have a 300‐Å‐thick magnetic layer (H_c=600 Oe, B_r =7200 G) and a 200‐Å‐thick protective layer. D₅₀=36 KFRPI and overwrite=−34 dB (24 KFRPI on 8 KFRPI) were obtained at 19.7 m/sec relative velocity and 0.25 μm head‐disk spacing. These values were superior to those for heads using Permalloy films (D₅₀=25 KFRPI, overwrite=−20 dB). It was concluded that CoZr amorphous thin film heads have superior capabilities for high density magnetic recording.