A ferrite sintered magnet comprising an M type Sr ferrite having a hexagonal structure as a main phase, wherein the ferrite sintered magnet does not substantially comprise a rare earth element and Co, a content of B is 0.005 to 0.9% by mass in terms of B.sub.2O.sub.3, and a content of Zn is 0.01 to 1.2% by mass in terms of ZnO.

A ferrite sintered magnet comprising an M type Sr ferrite having a hexagonal structure as a main phase, wherein the ferrite sintered magnet does not substantially comprise a rare earth element and Co, a content of B is 0.005 to 0.9% by mass in terms of B.sub.2O.sub.3, and a content of Zn is 0.01 to 1.2% by mass in terms of ZnO.

A novel transformer circuit employing multi-axis windings around a large magnetic billet receives and amplifies the energy from a flux of energetic waves emanating from the sun and other celestial bodies and entities throughout the environment. A clean source of solar energy can be harvested with an energy density that is at least 50 times greater than photon-based collectors.

To provide a ferrite sintered magnet having a high residual magnetic flux density (Br) and a high coercive force (HcJ), and also able to produce at a low cost. The ferrite sintered magnet includes a hexagonal M-type ferrite including A, R, Fe, and Co in an atomic ratio of A.sub.1-xR.sub.x(Fe.sub.12-yCo.sub.y).sub.zO.sub.19. A is at least one selected from Sr, Ba, and Pb. R is La only or La and at least one selected from rare earth elements. 0.13≤x≤0.23, 10.80≤(12−y)z≤12.10, and 0.13≤yz≤0.20 are satisfied.

A ferrite sintered magnet including ferrite grains having a hexagonal crystal structure. The ferrite grains satisfy 0.56≤W≤0.68 where W is an average value of circularities of the ferrite grains in a cross section parallel to an axis of easy magnetization.

A ferrite sintered magnet including ferrite grains having a hexagonal crystal structure. The ferrite grains satisfy 0.56≤W≤0.68 where W is an average value of circularities of the ferrite grains in a cross section parallel to an axis of easy magnetization.

To provide a ferrite sintered magnet having a high residual magnetic flux density (Br), a high coercive force (HcJ), a good production stability, and also able to produce at a low cost. The ferrite sintered magnet includes a hexagonal M-type ferrite including A, R, Fe, and Co in an atomic ratio of A.sub.1-xR.sub.x(Fe.sub.12-yCo.sub.y).sub.zO.sub.19. A is at least one selected from Sr, Ba, and Pb. R is La only or La and at least one selected from rare earth elements. 0.14≤x≤0.22, 11.60≤(12-y)z≤11.99, and 0.13≤yz≤0.17 are satisfied. 0.30≤Mc≤0.63 is satisfied in which Mc is CaO content (mass %) converted from a content of Ca included in the ferrite sintered magnet.

A ferrite sintered magnet 100 comprises M-type ferrite crystal grains 4 and multiple-crystal grain boundaries 6b surrounded by three or more of the M-type ferrite crystal grains 4. The ferrite sintered magnet 100 contains at least Fe, Ca, B, and Si, and contains 0.005 to 0.9 mass % of B in terms of B.sub.2O.sub.3. The multiple-crystal grain boundaries 6b contain Si and Ca, and in a case where the molar ratio of Ca to Si in the multiple-crystal grain boundaries 6b is represented by (Ca/Si).sub.G, the following formula is satisfied.
0.1<(Ca/Si).sub.G<0.9

A ferrite sintered magnet 100 comprises M-type ferrite crystal grains 4 and multiple-crystal grain boundaries 6b surrounded by three or more of the M-type ferrite crystal grains 4. The ferrite sintered magnet 100 contains at least Fe, Ca, B, and Si, and contains 0.005 to 0.9 mass % of B in terms of B.sub.2O.sub.3. The multiple-crystal grain boundaries 6b contain Si and Ca, and in a case where the molar ratio of Ca to Si in the multiple-crystal grain boundaries 6b is represented by (Ca/Si).sub.G, the following formula is satisfied.
0.1<(Ca/Si).sub.G<0.9

The magnet is a ferrite sintered magnet containing a ferrite phase having a magnetoplumbite-type crystal structure. The ferrite sintered magnet contains at least Ca, a metal element A, a metal element R, Bi, Fe, and a metal element M. The metal element A is at least one kind of element selected from the group consisting of Sr, Ba, and Pb, the metal element R is at least one kind of element selected from the group consisting of rare-earth elements including Y and essentially includes La, the metal element M is at least one kind of element selected from the group consisting of Co, Ni, Zn, Al, Cu, and Cr, and essentially includes Co, and when an atonic ratio of the metal elements is expressed by Formula (1), c, a, r, b, f, and m in Formula (1) satisfy the following Expressions (2) to (8).