IP Library › Granted Patent US 7,244,287
Granted Patent B2
US 7,244,287 · App. 10/895,938 · Granted Jul 17, 2007

Magnetic particle, its production method, magnetic recording medium and its production method

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Quick Facts
Patent No.
US 7,244,287
App. No.
10/895,938
Granted
Jul 17, 2007
Kind
B2
Abstract

The present invention relates to a method of producing a magnetic particle including forming a layer containing an alloy particle that can form a CuAu-type or Cu 3 Au-type hard magnetic ordered alloy phase on a support, oxidizing the layer, and annealing the layer in a non-oxidizing atmosphere. The invention also relates to a method of producing a magnetic particle including producing an alloy particle that can form a hard magnetic ordered alloy phase, oxidizing the alloy particle, and annealing the particle in a non-oxidizing atmosphere, and a magnetic particle produced by the foregoing production method. Further, the invention relates to a magnetic recording medium comprising a magnetic layer containing a magnetic particle and a method of producing a magnetic recording medium including forming a layer containing an alloy that can form the foregoing hard magnetic ordered alloy phase, oxidizing the layer, and annealing the layer in a non-oxidizing atmosphere.

Claims (5)

1. A method of producing a magnetic particle including producing an alloy particle that can form a CuAu-type or Cu 3 Au-type hard magnetic ordered alloy phase, oxidizing the alloy particle with an oxygen-containing gas, and annealing the particle in a non-oxidizing atmosphere.

2. A method of producing a magnetic particle according to claim 1 , wherein the atmosphere for the annealing is a reducing atmosphere, an annealing temperature is 450° C. or lower, and a retention time is 10 minutes or shorter.

3. A method of producing a magnetic particle according to claim 1 , wherein a third element other than elements that can form the CuAu-type or Cu 3 Au-type hard magnetic ordered alloy phase, is added to the alloy particle as an alloying element.

4. A method of producing a magnetic particle according to claim 1 , which comprises producing the alloy particle by a liquid phase method.

5. A method of producing a magnetic particle according to claim 1 , which comprises producing the alloy particle by a reverse micelle method.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 15, 2007
From: FUJIFILM HOLDINGS CORPORATION (FORMERLY FUJI PHOTO FILM CO., LTD.)
To: FUJIFILM CORPORATION
Reel/Frame 018904/0001 →