Abstract: 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.

Abstract: 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.