Browse Prior Art Database

A Glass Disk Structure with Improved Thermal Erasure

IP.com Disclosure Number: IPCOM000014887D
Original Publication Date: 2000-Apr-01
Included in the Prior Art Database: 2003-Jun-20
Document File: 2 page(s) / 100K

Publishing Venue

IBM

Abstract

Described is a glass disk structure for thermal erasure improvement. This disk structure consists of a thermal conducting layer and a seed layer as well as underlayer\magnetic layer\overcoat\lubrication layer. The function of the thermal conducting layer, such as CrV, Si, Cu, and Ag, is to conduct the heat generated due to head disk contact or particles/contamination fast enough to prevent thermal erasure of written data. The role of the seed layer is to ensure the epitaxtial growth of the sequentially deposited layers so that high recording density can be achieved.

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A Glass Disk Structure with Improved Thermal Erasure

   Described is a glass disk structure for thermal erasure improvement. This disk
structure consists of a thermal conducting layer and a seed layer as well as
underlayer\magnetic layer\overcoat\lubrication layer. The function of the
thermal conducting layer, such as CrV, Si, Cu, and Ag, is to conduct the heat
generated due to head disk contact or particles/contamination fast enough to
prevent thermal erasure of written data. The role of the seed layer is to ensure
the epitaxtial growth of the sequentially deposited layers so that high recording
density can be achieved.

   Thermal erasure occurs whenever the temperature of the magnetic layer of a
hard disk is higher than its Curie temperature. The thermal conductivity ( ~
0.76 W/mC) of glass substrates currently in use is much lower than that of AlMg
substrates (280 W/mC). Thus heat induced due to head-disk interaction , such as
contacting of the slider corner with the disk surfaces and head particles
dragging on the disk surfaces, could raise the magnetic temperature higher than
its Curie temperature and consequently erase previously written data. This
temperature rise of the magnetic layer could be reduced significantly with the
deposition of a high thermal conducting layer on the glass substrates.
Experimental results show that CrV, Si, Cu, and Ag thermal conducting layers
serve this purpose well (Fig. 1). On the other hand, those sputter deposited
thermal conducting layers are poly...