Active cancellation of mutual inductance in split-coil thin-film heads

Abstract

The consequences of using split-coil thin-film inductive heads for the recording process were investigated. The heads studied have two separate coils (the head is a four-terminal device); this allows the number of turns in the write and read process to be optimized independently. Unfortunately, at high frequencies the effect of mutual inductance between the coils offsets the potential reduction in the write inductance. The mutual inductance was characterized using both recording and impedance measurements. We demonstrate a novel, active technique for reducing the effect of the mutual inductance.