Patent ID: 6939575
Filing Date: 2005-09-06
Classification: B82Y,G11B,H01F,Y10T

Abstract:
1. A method of producing a ferromagnetic metal powder having an average long axis length of from 30 to 65 nm, a crystallite size of from 80 to 130 angstroms, a saturation magnetization (σs) of from 75 to 130 A·m 2 /kg, and an average oxide layer thickness of from 1.5 to 2.5 nm, the method comprising: reducing the oxide of a ferromagnetic metal element to obtain the ferromagnetic metal powder, subjecting the ferromagnetic metal powder obtained by reducing the ferromagnetic metal element to gradual oxidation treatment to make σs 120 to 150 A·m adhering, in water, at least one element selected from Al, Y, lanthanoid, Zr and W to the oxidized ferromagnetic metal powder obtained from the gradual oxidation treatment, performing heat treatment, and again performing the gradual oxidation treatment.