Rodney Edgar Lee

The study of recessed MR sensors with un-laminated and multi-laminated flux-guides

The authors have fabricated unshielded and shielded magnetoresistive (MR) sensors with various flux-guide configurations and studied their behavior using MR response and Kerr effect techniques. Results show interesting effects involving interactions of the MR sensor with the flux-guides and with the shielding environment, ranging from transverse bias enhancement effects of shields and flux-guides to the excitation of multidomain states in unshielded MR sensors by strong signal flux from the long back flux-guides. The multilaminated flux-guides are shown to be much better in noise behavior compared to the unlaminated flux-guides, although small amounts of jumps are still present, as expected from edge-curling wall magnetics. The presence of a long back flux-guide enhances the read sensitivity distinctly, but might also render flux-guide noise problems more critical in the operation of the sensor. >

A design concept of array heads

This paper describes a novel design concept and experimental hardware data of array heads for close-packed track recording. The heads are batch fabricated on wafers in a linear fashion. These 60-turn thin-film inductive heads are designed with 6 /spl mu/m pitch helical coils and planar side-by-side P1/G/P2 yokes structure. The linear head array is placed along the upstream-to-downstream direction of the track. By skewing the array slightly off the track direction, each head of the array aligns to an individual track. In this case, the track pitch is about 5 /spl mu/m, which is the yoke height. With this head arrangement, even though a thermal expansion causes the head-to-head distance to increase along the upstream-downstream direction, it does not cause a thermal induced track misregistration problem. The increased head-to-head distance only affects the timing of signals between tracks, which can be compensated by the channel electronics. Thus, the thermal induced track misregistration problem is eliminated using this design. The guard bands between tracks are not necessary, and a close-packed track recording is possible. A state of the art head impedance of the 60-turn head is obtained: 11 /spl Omega/ and 0.40 /spl mu/H. The gap-to-gap pitch is 100 /spl mu/m. The overall head-to-head isolation is greater than 50 dB at 10 MHz. Such a large isolation is realized by suppressing the capacitive coupling between lead wires using a ground plane and grounded wall structures. The tight winding of the helical coils reduces the magnetic coupling between the heads.

Batch-processed close-track array heads (abstract)

This article describes novel array heads for close packed track recording. The heads are batch fabricated on wafers in a linear fashion (Fig. 1). These 60-turn thin-film inductive heads are designed with 6 μm pitch helical coils and planar side-by-side P1/G/P2 yoke structures. The linear head array is placed along the upstream-to-downstream direction of the track. By skewing the array slightly off the track direction, each head of the array aligns to an individual track (Fig. 2). In this case, the track pitch is about 5 μm, which is the yoke height. With this head arrangement, even though thermal expansion causes the head-to-head distance to increase along the upstream–downstream direction, it does not cause a thermally induced track misregistration problem. The increased head-to-head distance only affects the timing of signals between tracks, which can be compensated by the channel electronics. Thus, the thermally induced track misregistration problem is eliminated using this design. The guardbands betwe...