H. Tanaka et al., Slider dynamics during continuous contact with textured and smooth disks in ultra low flying height, IEEE MAGNET, 37(2), 2001, pp. 906-911
Dynamics of a nano-slider during continuous contact with textured and smoot
h disks are studied using laser Doppler vibrometer, friction sensor, acoust
ic emission (AE) transducer and read back signal from a magneto-resistive h
ead on the slider. The flying height of the slider is controlled from flyin
g to contact at the same velocity by changing the environmental pressure. W
hen the slider flies over the textured disk, contact occurs at flying heigh
t of 14 nm, and friction and AE signal increase gradually with decreasing f
lying height. The increase in the amplitude of the slider vibration is with
in a few nanometers from flying to contact. When the slider flies over the
smooth disk, contact occurs at much lower flying height of 6 nm, However, f
riction, AE signal and the amplitude of the vibration show a steep increase
upon contact. Both pitch and roll vibration modes of the slider air bearin
g are strongly excited with the amplitude of about 10 nm, The pitch vibrati
on results in the slider impacting the disk surface severely. As the result
. the disk vibrates at the same frequency. In addition, thermal asperities
with extraordinary high amplitude are observed associated with the impacts
induced by the pitch vibration.