Disclosed herein are embodiments of composite hexagonal ferrite materials formed from a combination of Y phase and Z phase hexagonal ferrite materials. Advantageously, embodiments of the material can have a high resonant frequency as well as a high permeability. In some embodiments, the materials can be useful for magnetodielectric antennas.

A process for manufacturing ceramic-metal composite material, comprises dissolving ceramic powder into water to obtain an aqueous solution of ceramic; mixing metal powder having a multimodal particle size where largest particle size is one fourth of the minimum dimension of a device, with the aqueous solution of ceramic to obtain a powder containing ceramic precipitated on the surface of metal particles; mixing the powder containing ceramic precipitated on the surface of the metal particles, with ceramic powder having a particle size below 50μ.Math.τ.Math., to obtain a powder mixture; adding saturated aqueous solution of ceramic to the powder mixture to obtain an aqueous composition containing ceramic and metal; compressing the aqueous composition to form a disc of ceramic-metal composite material containing ceramic and metal; and removing water from the ceramic-metal composite material; wherein ceramic content of the disc is 10 vol-% to 35 vol-%. Alternatively, ceramic-ceramic composite material may be manufactured.

A ferrite sintered magnet comprises a plurality of main phase grains containing a ferrite having a hexagonal structure, wherein at least some of the main phase grains are core-shell structure grains each having a core and a shell covering the core; and wherein the minimum value of the content of La in the core is [La]c atom %; the minimum value of the content of Co in the core is [Co]c atom %; the maximum value of the content of La in the shell is [La]s atom %; the maximum value of the content of Co in the shell is [Co]s atom %; [La]c+[Co]c is 3.08 atom % or more and 4.44 atom % or less; and [La]s+[Co]s is 7.60 atom % or more and 9.89 atom % or less.

The present invention provides a ferrite sintered magnet comprising ferrite crystal grains having a hexagonal structure, wherein the ferrite sintered magnet comprises metallic elements at an atomic ratio represented by formula (1). In formula (1), R is at least one element selected from the group consisting of Bi and rare-earth elements, and R comprises at least La. In formula (1), w, x, z and m satisfy formulae (2) to (5). The above-mentioned ferrite sintered magnet further has a coefficient of variation of a size of the crystal grains in a section parallel to a c axis of less than 45%.
Ca.sub.1-w-xR.sub.wSr.sub.xFe.sub.zCo.sub.m  (1)
0.360≤w≤0.420  (2)
0.110≤x≤0.173  (3)
8.51≤z≤9.71  (4)
0.208≤m≤0.269  (5)

When manufacturing a magnetic body whose primary component is Ni—Zn ferrite, an iron oxide powder whose Mn content is 0.20 to 0.85 percent by mass is used as a raw material powder, or, in addition to using an iron oxide powder whose Mn content is 0.20 percent by mass or higher as a raw material powder, a mol ratio of Ni to Zn (Ni/Zn) in the ferrite material is determined based on the Mn content in the iron oxide powder and the raw material powders are compounded in such a way that the mol ratio is achieved. The magnetic body does not contain any additives as essential components other than the primary components of the Ni—Zn ferrite material. A coil component using the magnetic body has excellent direct-current superimposition property and magnetic permeability.

A ceramic composition contains Fe, Cu, Ni, Zn, Co, and Cr. When Fe, Cu, Ni, and Zn are converted to Fe.sub.2O.sub.3, CuO, NiO, and ZnO, respectively, and when a total amount of Fe.sub.2O.sub.3, CuO, NiO, and ZnO is 100 parts by mole, the ceramic composition contains 45.00 to 49.70 parts by mole Fe in terms of Fe.sub.2O.sub.3, 2.00 to 8.00 parts by mole Cu in terms of CuO, 19.40 to 45.40 parts by mole Ni in terms of NiO, and 1.00 to 27.00 parts by mole Zn in terms of ZnO. When Fe, Cu, Ni, and Zn are converted to Fe.sub.2O.sub.3, CuO, NiO, and ZnO, respectively, and when a total amount of Fe.sub.2O.sub.3, CuO, NiO, and ZnO is 100 parts by weight, the ceramic composition contains 5 to 100 ppm Co in terms of CoO and 10 to 400 ppm Cr in terms of Cr.sub.2O.sub.3.

A ceramic composition contains Fe, Cu, Ni, Zn, Co, and Cr. When Fe, Cu, Ni, and Zn are converted to Fe.sub.2O.sub.3, CuO, NiO, and ZnO, respectively, and when a total amount of Fe.sub.2O.sub.3, CuO, NiO, and ZnO is 100 parts by mole, the ceramic composition contains 45.00 to 49.70 parts by mole Fe in terms of Fe.sub.2O.sub.3, 2.00 to 8.00 parts by mole Cu in terms of CuO, 19.40 to 45.40 parts by mole Ni in terms of NiO, and 1.00 to 27.00 parts by mole Zn in terms of ZnO. When Fe, Cu, Ni, and Zn are converted to Fe.sub.2O.sub.3, CuO, NiO, and ZnO, respectively, and when a total amount of Fe.sub.2O.sub.3, CuO, NiO, and ZnO is 100 parts by weight, the ceramic composition contains 5 to 100 ppm Co in terms of CoO and 10 to 400 ppm Cr in terms of Cr.sub.2O.sub.3.

A ceramic composition contains Fe, Cu, Ni, Zn, Co, and Cr. When Fe, Cu, Ni, and Zn are converted to Fe.sub.2O.sub.3, CuO, NiO, and ZnO, respectively, and a total amount of Fe.sub.2O.sub.3, CuO, NiO, and ZnO is 100 parts by mole, the ceramic composition contains from 48.20 to 49.85 parts by mole Fe in terms of Fe.sub.2O.sub.3, from 2.00 parts to 8.00 parts by mole Cu in terms of CuO, from 11.90 to 18.70 parts by mole Ni in terms of NiO, and from 27.00 to 33.50 parts by mole Zn in terms of ZnO. When Fe, Cu, Ni, and Zn are converted to Fe.sub.2O.sub.3, CuO, NiO, and ZnO, respectively, and a total amount of Fe.sub.2O.sub.3, CuO, NiO, and ZnO is 100 parts by weight, the ceramic composition contains from 5 to 100 ppm Co in terms of CoO and from 10 to 400 ppm in terms of Cr.sub.2O.sub.3.

A method for manufacturing a sintered body, the method including heating a mixture that contains a plurality of particles of a metal oxide having a spinel-type structure, and a metal acetylacetonate under pressure at a temperature of from a melting point or higher of the metal acetylacetonate to 600° C. or lower, to form a sintered body that contains the metal oxide having the spinel-type structure.

A method for manufacturing a sintered body, the method including heating a mixture that contains a plurality of particles of a metal oxide having a spinel-type structure, and a metal acetylacetonate under pressure at a temperature of from a melting point or higher of the metal acetylacetonate to 600° C. or lower, to form a sintered body that contains the metal oxide having the spinel-type structure.