Objects are to provide a ferrite powder having a residual magnetization and a coercive force larger than those of spherical hard ferrite particle, and magnetic permeability μ″ is maximum in a specific frequency range, a manufacturing method thereof, a resin compound containing the ferrite powder, and a molded product made from the resin compound. To achieve the objects, a hexagonal plate shaped ferrite powder containing 7.8 to 9 wt % of Sr, 61 to 65 wt % of Fe, and 0.1 to 0.65 wt % of Mg, a manufacturing method thereof, a resin compound containing the hexagonal plate shaped ferrite powder, and a molded product made from the resin compound are employed.

Objects are to provide a ferrite powder having a residual magnetization and a coercive force larger than those of spherical hard ferrite particle, and magnetic permeability μ″ is maximum in a specific frequency range, a manufacturing method thereof, a resin compound containing the ferrite powder, and a molded product made from the resin compound. To achieve the objects, a hexagonal plate shaped ferrite powder containing 7.8 to 9 wt % of Sr, 61 to 65 wt % of Fe, and 0.1 to 0.65 wt % of Mg, a manufacturing method thereof, a resin compound containing the hexagonal plate shaped ferrite powder, and a molded product made from the resin compound are employed.

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).

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).

A production method of a Fe.sub.16N.sub.2 based permanent magnet includes the following steps: 1) obtaining a Fe.sub.16N.sub.2 compound in a form of micro flakes by applying a nitriding process to α′-Fe powders of micro or nano sizes; 2) forming a structure by combining a polymer material with the Fe.sub.16N.sub.2 compound and utilizing a 3D printer; and 3) applying a magnetization process to the structure obtained in step 2 to obtain a magnetized structure and carrying out a heat treatment process to the magnetized structure to obtain the Fe.sub.16N.sub.2 based permanent magnet. The production method is continuous, less difficult, and less costly compared to the production of previous permanent magnets.

A production method of a Fe.sub.16N.sub.2 based permanent magnet includes the following steps: 1) obtaining a Fe.sub.16N.sub.2 compound in a form of micro flakes by applying a nitriding process to α′-Fe powders of micro or nano sizes; 2) forming a structure by combining a polymer material with the Fe.sub.16N.sub.2 compound and utilizing a 3D printer; and 3) applying a magnetization process to the structure obtained in step 2 to obtain a magnetized structure and carrying out a heat treatment process to the magnetized structure to obtain the Fe.sub.16N.sub.2 based permanent magnet. The production method is continuous, less difficult, and less costly compared to the production of previous permanent magnets.

The ferrite powder of the present invention is a ferrite powder containing a plurality of ferrite particles, wherein the ferrite particles each are a single crystal body having an average particle diameter of 1-2,000 nm, and have a polyhedron shape, and wherein the ferrite particles each contain 2.0-10.0 mass % of Sr, and 55.0-70.0 mass % of Fe.

The ferrite powder of the present invention is a ferrite powder containing a plurality of ferrite particles, wherein the ferrite particles each are a single crystal body having an average particle diameter of 1-2,000 nm, and have a polyhedron shape, and wherein the ferrite particles each contain 2.0-10.0 mass % of Sr, and 55.0-70.0 mass % of Fe.

A magnetic encoder in which a support member and a plastic magnet do not adhere to each other is manufactured using a mold. The plastic magnet has a turning molded portion on the outer circumferential side thereof. The gate of the mold is an inner-diameter-side disk gate and a length L thereof in the axial direction is in a range of 0.2 mm≤L≤0.6 mm. The tensile strength of the material of the plastic magnet is 65 MPa or more and the Young's modulus thereof is 4000 MPa or more and 15000 MPa or less. The method includes a step of opening the mold and placing the support member as an insert object in the mold, and a step of closing the mold and injecting a melted material of the plastic magnet into a cavity through the disk gate.

A magnet structure is a magnet structure for a TMR element which is an MR element. The magnet structure includes a bonded magnet compact that has a first main surface facing the TMR element, and a second main surface on a side opposite to the first main surface; and a tubular member that supports the bonded magnet compact. The bonded magnet compact has a gate portion which is provided on the second main surface and includes a gate mark formed by performing injection molding. The gate portion is provided at a position overlapping a center on the second main surface when seen from the second main surface side.