Fabrication of submicron trackwidth thin-film head and its inductance-saturation characteristics

A write head with submicron trackwidth was fabricated. Its main feature is to use the thickness of magnetic films to replace the stripe width of the head core as the recording trackwidth. Hard-cured photoresist was used to isolate coil from magnetic films and round off the sharp corner at the steps of bottom coil. Round steps with height similar to300 nm was shown by the scanning focused ion beam microscope images of cross section of the core. The inductance-saturation characteristic was measured by superimposing an oscillating current on a DC bias current. The experimental results of inductance do not coincide with the theoretical values. The analysis indicated that the differences are mainly originated from the leakage flux and demagnetization while the flux flowed in the magnetic circuit. The inductance curve as function of DC bias current exhibits a series of step-like discontinuities. The location and magnitude of these discontinuities are related to the shape and size of the core, and a satisfactory interpretation was given. It is believed that large saturation bias current results in that the stability of the head is insusceptible to the amplitude of signal during its operation. (C) 2003 Elsevier B.V. All rights reserved.