Dynamic field distributions of thin film inductive heads

Abstract

Dynamic recording fields of thin film inductive disk drive heads and their relationships to drive current, pole thickness and pole materials have been investigated. Electron beam tomography was used to directly observe the recording fields. With permalloy heads, improved frequency responses were achieved by exciting the magnetic core with higher drive currents. However, increases in the pole thickness significantly degraded the frequency responses. The amorphous CoTaZr head showed superior frequency response, and constant field intensity was maintained up to 30 MHz, regardless of drive current.

The effect of rise time and field gradient on nonlinear bit shift in thin film heads

“…This difference is due to the fact that in the model the frequency response of the head was not changed with the write current while the rise time does improve with increasing write current in actual heads. The improvement in frequency response at higher write current has been attributed to increased domain wall damping at higher write current [13]. The agreement between model and data is qualitatively very good.…”