Improved algorithm and method for characterizing instability and write-induced magnetic center shifts for MR head

We have developed new algorithms and methods for characterizing a write-induced magnetic read center shift for MR heads from on-track and off-track readback signals. Mechanisms for the instability can be characterized by a cross correlation coefficient of V/sub A/ and V/sub c/, r[V/sub A/,V/sub C/], where V/sub A/ and V/sub C/ are half track amplitudes (50 % off-track) of signals reading from two adjacent servo-burst-like bursts A and C. Instabilities of the head resulting purely from changes in the read sensitivity of the MR head bring about a unity of the coefficient. Instabilities of the head resulting purely from shifts of the magnetic read center bring about a negative unity of the coefficient. A correlation function developed in this work correlates with the shift of the MR read center well.