Spin valve magnetoresistive sensor with self-pinned laminated layer and magnetic recording system using the sensor

摘要

An SVMR sensor (60) having a self-pinned laminated layer (70) with at least two ferromagnetic films (72,74) antiferromagnetically coupled to one another across a thin antiferromagnetically (AF) coupling film (73). Since the two ferromagnetic films (72,74) in this laminated layer (70) have their magnetic moments aligned antiparallel, their two magnetic moments can be made to essentially cancel by making the two ferromagnetic films (72,74) of substantially the same thickness. The magnetic field energy generated by the signal field acting on this laminated layer (70) will be significantly less than the effective anisotropy energy of the laminated layer (70). As a result, the laminated layer (70) will not rotate in the presence of the signal field, but will be "self-pinned". A hard-bias or exchange bias layer in not needed, also eliminating the need for Ni-Mn and its associated high-temperature process. $$