Perpendicular Hard Disk Media for Contact SPT Head Recording System

Abstract

Co-Cr/Ni-Fe double layer hard disk medium for a new contact SPT head system was investigated in regard to its design. The medium was prepared with an RF sputtering system, sequentially depositing a Cr or a Ti underlayer, a soft-magnetic backlayer, a Co-Cr recording layer and a Si0 2 protective layer. The Cr underlayer with thickness of 0.025 f11n realized the most excellent crystallinity of the backlayer. The largest signal-to-noise ratio of 35 dB was obtained with thickness of 0.5 to 1.0 f11n for the Cu-Mo-Permalloy backlayer, and with about 2.0 f11n thickness for the Nb-Permalloy one, respectively. Addition of Ta to a Co-Cr system was also examined to narrow the anisotropy field distribution. It was found that a high output at high recording densities could be obtained for the narrowed ani.'IOtropy field distribution.

Theoretical and Experimental Prospects of Perpendicular Magnetic Recording

“…protective layer were successively deposited onto the grass substrate by sputtering [24]. The average roughness, Ra' and the maximum height, ~ax' of the hard disk, measured using a stylus surface profilometer, were around 2.5 nm and 12.5 nm, respectively.…”

Status Report: Perpendicular Contact Recording on Rigid Media

“…Efforts directed toward improving the perpendicular anisotropy of sputtered CoCrX alloy films and eliminating the poorly oriented initial layers (several tens of nanometers thick) have met with some success through the use of various seed layers to enhance crystallographic texture and microstructure [2]. However, this ha~ proved to be more difficult when such films are grown on soft magnetic underlayers, which serve as a flux return path with single pole type heads, since it is undesirable to break up exchange coupling between the two filins, as would be the case with most seed layers [3][4][5][6]. This problem becomes increasingly important as attempts are made to reduce the storage layer thickness in order to increase the interaction between the pole and soft magnetic underlay er and exploit the advantages of contact recording.…”