Dynamics of glide head in the proximity contact regime

The intrinsic glide capability of a magnetic disk is typically assessed by the glide avalanche test with an acoustic emission (AE) or a piezoelectric transducer (PZT) sensor and is found to be a function of asperity height distribution. In this work, the dynamics of a glide head in the near contact regime is investigated. Both the laser Doppler vibrometer (LDV) and PZT techniques are used to monitor the head dynamics during the touchdown process on disks with different roughness. It is shown that the glide avalanche readings can be affected by the collapse of the air bearing. The comparison of the PZT and LDV responses during the glide avalanche process indicates a general agreement between these two methods.