Oxide-type, magnetic material and its production method, and sintered ferrite magnet and its production method

A method for producing an oxide-type, magnetic material based on ferrite having a hexagonal structure and comprising Ca, an R element which is at least one rare earth element indispensably including La, Ba, Fe and Co as indispensable elements, the composition ratios of Ca, R, Ba, Fe and Co being represented by the following general formula:

• Ca1-x-yRxBayFe2n-zCoz (by atomic ratio),
• wherein (1-x-y), x, y, z and n are numbers representing the amounts of Ca, the R element, Ba and Co and a molar ratio, respectively, meeting the following conditions:
• 0.2≦x≦0.65,
• 0.001≦y≦0.2,
• 0.3≦1-x-y≦0.6,
• 0.03≦z≦0.65, and
• 4≦n≦7,
• said method comprising the steps of mixing a Ca compound, an R compound, a Ba compound, an iron compound and a Co compound to obtain said composition, and calcining the resultant mixture.

A sintered ferrite magnet having an M-type ferrite structure, comprising Ca, an R element which is at least one rare earth element indispensably including La, Ba, Fe and Co as indispensable elements, the composition ratios of Ca, R, Ba, Fe and Co being represented by the following general formula:

• Ca1-x-yRxBayFe2n-zCoz (by atomic ratio),
• wherein (1-x-y), x, y, z and n are numbers representing the amounts of Ca, the R element, Ba and Co and a molar ratio, respectively, meeting the following conditions:
• 0.2≦x≦0.65,
• 0.001≦y≦0.2,
• 0.3≦1-x-y≦0.65,
• 0.03≦z≦0.65, and
• 4≦n≦7.

A method for producing a sintered ferrite magnet having an M-type ferrite structure and comprising Ca, an R element which is at least one rare earth element indispensably including La, Ba, Fe and Co as indispensable elements, the composition ratios of Ca, R, Ba, Fe and Co being represented by the following general formula:

• Ca1-x-yRxBayFe2n-zCoz (by atomic ratio),
• wherein (1-x-y), x, y, z and n are numbers representing the amounts of Ca, the R element, Ba and Co and a molar ratio, respectively, meeting the following conditions:
• 0.2≦x≦0.65,
• 0.001≦y≦0.2,
• 0.3≦1-x-y≦0.65,
• 0.03≦z≦0.65, and
• 4≦n≦7,
• said method comprising a mixing step of starting materials therefor, a calcining step, a pulverizing step, a molding step and a sintering step.

A sintered ferrite magnet having an M-type ferrite structure, comprising Ca, an R element which is at least one rare earth element indispensably including La, Ba, Sr, Fe and Co as indispensable elements, the composition ratios of Ca, R, Ba, Sr, Fe and Co being represented by the following general formula:

• Ca1-x-yRx(Ba1-aSra)yFe2n-zCoz (by atomic ratio),
• wherein (1-x-y), x, y, a, z and n are numbers representing the amounts of Ca, the R element, Ba, Sr and Co and a molar ratio, respectively, meeting the following conditions:
• 0.2≦x≦0.65,
• 0.001≦y≦0.2,
• 0.3≦1-x-y≦0.65,
• 0<a≦0.5,
• 0.03≦z≦0.65, and
• 4≦n≦7.

A method for producing a sintered ferrite magnet having an M-type ferrite structure and comprising Ca, an R element which is at least one rare earth element indispensably including La, Ba, Sr, Fe and Co as indispensable elements, the composition ratios of Ca, R, Ba, Sr, Fe and Co being represented by the following general formula:

• Ca1-x-yRx(Ba1-aSra)yFe2n-zCoz (by atomic ratio),
• wherein (1-x-y), x, (y-a), a, z and n are numbers representing the amounts of Ca, the R element, Ba, Sr and Co and a molar ratio, respectively, meeting the following conditions:
• 0.2≦x≦0.65,
• 0.001≦y≦0.2,
• 0.3≦1-x-y≦0.65,
• 0<a≦0.5,
• 0.03≦z≦0.65, and
• 4≦n≦7,
• said method comprising a mixing step of starting materials therefor, a calcining step, a pulverizing step, a molding step and a sintering step, a Sr compound being added in said mixing step and/or said pulverizing step.