Perpendicular recording (or Perpendicular Magnetic Recording, PMR) is a recently implemented technology for data recording on hard disk. It was first proven advantageous by Shun-ichi Iwasaki, then professor of the Tohoku University in Japan in 1976. In longitudinal recording, the magnetic orientation of the data bits is aligned horizontally, its nameindicates, parallel to the surface of the disk. By contrast, in perpendicular recording, the magnetic orientation of the data bits is aligned vertically, perpendicular to the disk. In this orientation, materials and smaller crystalline grains can be used wherein it is harder to reverse the magnetic orientation, resulting in smaller physical bits that are still stable at room temperature.
A perpendicular magnetic recording disk has an under layer structure that causes the magnetic layer to have perpendicular magnetic anisotropy and high signal-to-noise ratio (SNR). The under layer structure comprises a B2 type body-centered-cubic (BCC) material, such as the binary alloys NiAl, RuAl and RuTi, as an under layer, and a Ti or TiCr alloy sublayer formed directly on the under layer. The magnetic layer, such as a CoCrPt alloy, is deposited directly on the sublayer. The magnetic layer has perpendicular magnetic anisotropy due to the sublayer yet excellent SNR because of the smaller grain size of the sublayer material formed directly on the B2 type under layer
1 comments: on "Perpendicular Recording"
I need presentation of this topic. Thanks for the report.
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