High-B/sub s/ low-H/sub c/ CoNiFe films with bcc single-phase structure for write heads

Abstract

We studied electroplated CoNiFe films with a bcc structure and large magnetic flux density (B/sub s/), and by changing the film composition obtained various surfaces and magnetic properties for such films. Films plated under conventional conditions have a high B/sub s/ of 2.0 T and large coercivity (H/sub c/) of 30 Oe, which are caused by the large grain size in the bcc structure. We found that by plating the films with high current density, the grain size decreased and as a result, low H/sub c/ of 15 Oe is obtained while preserving high B/sub s/. Recording heads fabricated with such bcc-CoNiFe film show good overwrite performance.