Disk roughness and contact induced FH vibration at sub-10nm FH

As flying height is reduced to the sub-10nm range, intermittent slider-disk contacts occur to modulate the head-disk spacing and thus deteriorate the performance of the magnetic recording system. Therefore, the contact induced flying height vibration has to been monitored and reduced in order to maintain a reliable head disk interface in the proximity recording regime. This paper reports and attempts to explain the relationship between the disk roughness and such induced vibrations by studying the flying height signal on the in-situ flying height tester. Sliders with 6-7 nm FH are used to test the head disk contact on the disks with different roughness. The head-disk contacts on the smoother disk tend to lengthen in duration compared with those on the rough disk. The rough disk shows the clear concentrated vibration modes, whilst the vibration contents of the smooth disk are more evenly distributed across the wide spectrum. The observation from the flying height signal also shows that the bouncing height on the smooth disk is much higher than that on the rough disk.