An experimental correlation of slider-disk contact detection between piezoelectric and electrical resistance measurements

The author presents two velocity avalanche methods which can be used to determine slider-disk spacing as well as to calibrate individual piezoelectric-transducer (PZT) sliders. The measurements, which were made using a specially developed asperity disk, indicate that the PZT signals must be high-pass-filtered to provide accurate contact detection. When the PZT results are compared to electrical resistance methods it is shown that both methods detect given asperities at the same velocity (fly height), indicating that PZT detection is both sensitive and accurate