Magnetic recording medium and method for its production
AssigneeMitsubishi Chemical Corporation
InventorFumiaki Yokoyama
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Abstract
A magnetic recording medium comprising a non-magnetic substrate and a magnetic alloy layer formed on the substrate with a non-magnetic primer layer containing chromium as the main component interposed therebetween, wherein the magnetic alloy layer contains cobalt and nickel as the main components and not more than 8 atomic % of boron and has been formed by sputtering under such a condition that a negative bias voltage is applied to the non-magnetic substrate.
Claims21
A magnetic disk recording medium, comprising:
- a non-magnetic disk substrate;
- a non-magnetic primer layer thereon containing chromium, and
- a magnetic alloy layer thereon consisting of cobalt, not more than 27 atomic % of nickel, from 5 to 26 atomic % of chromium and from 1 to 7 atomic % of boron, formed by sputtering under such a condition that a negative bias voltage is applied to the non-magnetic substrate relative to the grounded portion of the main body of the sputtering apparatus, wherein said magnetic disk recording medium has a coercive force of at least 1500 Oe.
The magnetic recording medium according to claim 14, wherein the magnetic alloy layer has been formed by sputtering under such a condition that a negative bias voltage of from -40 to -250 V is applied to the non-magnetic substrate relative to the grounded portion of the main body of a high frequency magnetron sputtering apparatus.
Dependencies are inferred from the claim text.