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AssigneeDowa Electronics Materials Co., Ltd.
InventorsKenji Masada, Tomoyuki Ishiyama, Gousuke Iwasaki
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A hexagonal crystal ferrite magnetic powder having high magnetic characteristics while having a small particle volume and a high specific surface area is provided, and a high-density magnetic recording medium using the powder. A method for producing a hexagonal crystal ferrite formed using a glass crystallization method includes the steps of: mixing a glass matrix with raw materials including iron, bismuth, a divalent metal (M1), a tetravalent metal (M2), any one kind (A) of barium, strontium, calcium, and lead, and at least one kind of rare earth element (represented by R) having a mole equal to or less than that of the iron; heating the mixed raw material to obtain a glass body; quenching the glass body, pulverizing the glass body, and performing a heat treatment, and washing the glass body after the heat treatment with an acid solution.
A method for producing a hexagonal crystal ferrite formed using a glass crystallization method, the method comprising the steps of:
A hexagonal crystal ferrite powder formed from iron, bismuth, a divalent metal (represented by M1), a tetravalent metal (represented by M2), any one kind (A) of barium, strontium, calcium, and lead, and at least one kind of rare earth element (represented by R);
A hexagonal crystal ferrite powder formed from iron, bismuth, a divalent metal (represented by M1), a tetravalent metal (represented by M2), any one kind (A) of barium, strontium, calcium, and lead, and at least one kind of rare earth element (represented by R), wherein the powder has an average particle volume of 100 to 2500 nm3.
A hexagonal crystal ferrite powder formed from iron, bismuth, a divalent metal (represented by M1), a tetravalent metal (represented by M2), any one kind (A) of barium, strontium, calcium, and lead, and at least one kind of rare earth element (represented by R);
Dependencies are inferred from the claim text.