Ikuo Yoshihara

Computer simulation of MR response to transverse magnetic fields

The magnetoresistive (MR) response of an MR sensor with shields to a uniform applied field was calculated through a micromagnetic simulation, and the results were compared with those from an MR sensor without shields. A uniform longitudinal field, resulting from boundary pinning by exchange-biased antiferromagnetic films, was applied to the MR films of the two sensors. There are three differences between the MR sensors with and without shields: first, the slope of the MR response with shields near an applied field of zero is smaller than the slope of the response without shields. Second, the response of the shielded MR sensor has no subpeak, while the response of the unshielded MR sensor has a subpeak. Third, the output of the shielded MR sensor hardly decreases in a large field (1000 Oe), while the output of the unshielded MR sensor quickly falls to a small value in a field of 300 Oe. These differences are due to attenuated magnetic fields in the gap between the two shields except near the air bearing surface (ABS).