Victor W. Hesterman

Dual stripe magnetoresistive heads for high density recording

The design and recording performance of dual stripe magnetoresistive read/inductive write heads with read widths of 4 /spl mu/m and write widths of 4.5 /spl mu/m are described. A linear density of 75 kfci (D50) was measured in heads with shield-to-shield spacing of 420 nm and 70 nm of dielectric separating the two magnetoresistive stripes. Large signal amplitude, linear cross-track profile, and good second harmonic suppression are observed in accordance with theoretical expectations. Readback waveforms contain little baseline shift and the ratio of positive to negative peak amplitudes is very close to unity. Stable signals are seen for heads with and without exchange stabilization. Conductor topography in the read head is replicated in the write head and can adversely affect cross-track behavior. Non-planarity of the write head must be considered in the design of shared pole magnetoresistive heads. >

A magnetoresistive gradiometer for detection of perpendicularly recorded magnetic transitions

A magnetoresistive gradiometer to detect perpendicularly recorded transitions has been conceived. It utilizes two parallel magnetoresistive stripes with opposing sense/bias currents. The magnetoresistive elements mutually bias each other with the same polarity bias fields. The fields of a perpendicular transition centered between the two stripes increase the resistance of one stripe while decreasing that of the other, therefore providing maximum output signal using differential detection. The detector provides a Lorenztian‐type readback waveform and rejection of common‐mode noise. The experimental readback waveform exhibited a pulse width at half maximum of 0.7 μm for a head flying at 0.2 μm above the media surface.