| More aggressive approaches to delaying the
superparamagnetic effect could involve perpendicular recording,
proposed to reduce the demagnetizing influences of adjacent
bits and improve bit stability. A new head design for writing,
a perpendicular inductive head, is substantially different than
the inductive ring head now in use for longitudinal recording
throughout the industry. The perpendicular head writes magnetic
transitions vertically within the recording medium by orienting
the write field perpendicular to the direction of the recording
film surface. The magnetic field created by this perpendicular
head returns to this element through a magnetically soft underlayer
within the medium, or return path. In this way the recording
medium now lies within the write gap. The resulting perpendicular
write fields could be up to 2X larger than today's longitudinal
write fields and this enables writing information on high coercivity
media that is inherently more thermally stable.
In longitudinal recording, the fields between two adjacent
bits with opposing magnetizations are separated by a transition
space. In perpendicular recording the bits do not directly
oppose each other resulting in a significantly reduced transition
packing. This allows bits to be more closely packed with sharper
transition signals, facilitating easier bit detection and
error correction. The potential for higher areal density results. |
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