Performance of yoke type GMR heads

Yoke type spin valve giant magnetoresistive (GMR) heads with a track width of 70 and 10 /spl mu/m are studied. The head design has the sensor on top. The output of the heads is found to be up to 10 times larger than similar heads with a 30 nm Ni-Fe MRE linearized using a barberpole. The crucial role of the free layer permeability /spl mu//sub r/ and the ferromagnetic interlayer coupling with respect to the head performance is analysed. This is argued to give design rules for the GMR material. The applied FeMn exchange biasing is shown to become unreliable above T=105/spl deg/C.