Effect of GMR amplitude asymmetry at track edge on servo position error signal

The effect of track-edge amplitude asymmetry on position-error signal, PES, of spin-valve GMR heads was investigated. Cross-track profiles of both amplitude and amplitude asymmetry are showed along with the PES line of the head. The results indicated that amplitude-asymmetry effect from servo burst is finite but not significant enough to alter PES sensitivity, or the slope of PES line. However, it is shown experimentally that the PES linearity is functionally correlated with asymmetry of the servo bursts, which substantiates the track-edge effect of spin-valve heads.