Perpendicular write-head remanence characterization using a contact scanning recording tester

In this study, an experimental method for characterizing perpendicular write-head pole-tip remanence using a contact scanning recording tester is presented. The head remanence is characterized by imaging the written patterns generated by perpendicular write heads on dc-saturated perpendicular media. Write-head footprints are recorded with pulsed unidirectional currents while the head is stationary, followed by scanning the head in various directions at current-off state. Sufficient head remanent field yields written traces during the current-off scan. Projection of traces in multiple scanning directions enables pinpointing of the pole-tip remanence locations. It is found that the traces written by the remanent field appear only when pulse current amplitudes exceed a certain threshold value. The strength of remanent field also shows a dependence on current pulse polarity. The “stiffness” of the remanence is characterized by the amplitude of the opposite write current needed to eliminate the remanent field.