Beyond discrete tracks: Other aspects of patterned media

Abstract

The surface of a thin-film disk can be patterned using standard lithographic techniques to form discrete tracks as narrow as 0.5 μm. These studies have been extended to patterns formed when an etched track is broken into discrete segments by etching away some portions of a discrete track. Abrupt changes in the magnetization can be obtained by dc erasing the medium, giving readback signals with ∼50% of the amplitude of conventional transitions when the gap of the readback head is aligned with the edge of the media pattern. The implications of these results for servo and read-only applications are discussed.

Micromagnetic simulations of discrete track media

“…Another issue is controlling the width of the erase bands at the edges of written tracks: these can be a major source of noise. Discrete track media (DTM), in which the erase bands are removed by patterning the recording layer into land and groove regions, are expected to be able to support higher track densities than continuous media [1][2][3].…”

Effect of ion beam patterning on the write and read performance of perpendicular granular recording media

“…P ATTERNED media is one of many schemes proposed to overcome the thermal stability problem that arises in the traditional scaling approach to achieving higher areal density using conventional recording media [1]- [7]. Instead of decreasing the grain size as the bit cell size is reduced in order to maintain signal-to-noise, the media is lithographically patterned into single magnetic domain islands.…”

The ultra high track density head positioning method of disk drives

“…At the same time, another method called " Pre-Embossed Rigid Magnetic disk (PERM)" that is similar to the former has been proposed too [6,7].Both these two methods use a plurality of discrete blocks of magnetic material to form the servo patterns, but they are different in magnetizing these blocks. In GHP these blocks are magnetized with alternating current, but in PERM with direct current.…”