Study of recessed MR sensors with unlaminated 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