Observation of Recording Pole Instability in Perpendicular Recording

In this study we report variable footprint shapes indicating recording pole instability. We extend the spin-stand "footprint" measurements to also evaluate recording pole instability. The observed recording pole instability causes degradation of the system performance and should be avoided. The switching between these states is random and occurs after high frequency head excitation. The higher residual overwrite signal at negative offset from the track center suggests that the recording pole switches to a different state with a smaller effective field at the corresponding pole corner.