Disclosed herein are embodiments of an enhanced resonant frequency hexagonal ferrite material, such as Y-phase hexagonal ferrite material, and methods of manufacturing. In some embodiments, sodium or potassium can be added into the crystal structure of the hexagonal ferrite material in order to achieve improved resonant frequencies in the range of 500 MHz to 1 GHz useful for radiofrequency applications.

Disclosed herein are embodiments of an enhanced resonant frequency hexagonal ferrite material and methods of manufacturing. The hexagonal ferrite material can be Y-phase hexagonal ferrite material, such as those including strontium. In some embodiments, oxides consistent with the stoichiometry of Sr.sub.3Co.sub.2Fe.sub.24O.sub.41, SrFe.sub.12O.sub.19 or CoFe.sub.2O.sub.4 can be used form an enhanced hexagonal ferrite material.

Disclosed herein are embodiments of an enhanced resonant frequency hexagonal ferrite material and methods of manufacturing. The hexagonal ferrite material can be Y-phase strontium hexagonal ferrite material. In some embodiments, sodium can be added into the crystal structure of the hexagonal ferrite material in order to achieve high resonance frequencies while maintaining high permeability.

In an embodiment, a magneto-dielectric material comprises a polymer matrix; a plurality of hexaferrite microfibers; wherein the magneto-dielectric material has a permeability of 2.5 to 7, or 2.5 to 5 in an x-direction parallel to a broad surface of the magneto-dielectric material and a magnetic loss tangent of less than or equal to 0.03; as determined at 1 GHz, or 1 to 2 GHz.

Disclosed herein is a hexaferrite composite comprising polytetrafluoroethylene; and greater than or equal to 40 vol %, or 40 to 90 vol % a plurality of Co.sub.2Z hexaferrite particles based on the total volume of the polytetrafluoroethylene and the plurality of Co.sub.2Z hexaferrite particles on a void-free basis; wherein the hexaferrite composite has a porosity of greater than or equal to 10 vol % based on the total volume of the hexaferrite composite; wherein the hexaferrite composite has a permeability of greater than or equal to 2.5 and a ratio of the permeability to the permittivity of greater than or equal to 0.4, both determined at 500 MHz.

In an aspect, a ferrite composition comprises a RuCo.sub.2Z ferrite having the formula: (Ba.sub.3-xM.sub.x)Co.sub.2(MRu).sub.yFe.sub.24-2y-zO.sub.41, wherein M is at least one of Sr, Pb, or Ca; M is at least one of Co, Zn, Mg, or Cu; x is 1 to 3; y is greater than 0 to 2; and z is 4 to 4. In another aspect, an article comprises the ferrite composition. In yet another aspect, method of making the ferrite composition comprises mixing ferrite precursor compounds comprising Fe, Ba, Co, and Ru; and sintering the ferrite precursor compounds in an oxygen atmosphere to form the RuCo.sub.2Z ferrite.

In an aspect, a multiphase ferrite comprises a Co.sub.2W phase that is optionally doped with Ru; a CFO phase having the formula Me.sub.rCo.sub.1rFe.sub.2+zO.sub.4, wherein Me is at least one of Ni, Zn, or Mg, r is 0 to 0.5, and z is 0.5 to 6 0.5; and a CoRu-BaM phase having the formula BaCo.sub.x+yRu.sub.yFe.sub.12(2/3)x2yO.sub.19, wherein x is 0 to 2, y is 0.01 to 2; and the Ba can be partially replaced by at least one of Sr or Ca. In another aspect, a composite can comprise a polymer and the multiphase ferrite. In yet another aspect, a method of making a multiphase ferrite can comprise mixing and grinding a CoRu-BaM phase ferrite and a CFO phase ferrite to form a mixture; and sintering the mixture in an oxygen atmosphere to form the multiphase ferrite.

There is provided a magnetic material that has an excellent electromagnetic wave absorption performance in a wide frequency range even under low temperature and high temperature environments and that ensures the absorption performance, and provided a magnetic material as a mixture of a magnetic material having positive slope of change in coercive force dependent on temperature, and a magnetic material having negative slope of change in coercive force dependent on temperature.

Radiofrequency and other electronic devices can be formed from textured hexaferrite materials, such as Z-phase barium cobalt ferrite Ba.sub.3Co.sub.2Fe.sub.24O.sub.41 (Co.sub.2Z) having enhanced resonant frequency. The textured hexaferrite material can be formed by sintering fine grain hexaferrite powder at a lower temperature than conventional firing temperatures to inhibit reduction of iron. The textured hexaferrite material can be used in radiofrequency devices such as circulators or telecommunications systems.

Disclosed herein are embodiments of an enhanced resonant frequency hexagonal ferrite material and methods of manufacturing. The hexagonal ferrite material can be Y-phase hexagonal ferrite material, such as those including strontium. In some embodiments, oxides consistent with the stoichiometry of Sr.sub.3Co.sub.2Fe.sub.24O.sub.41, SrFe.sub.12O.sub.19 or CoFe.sub.2O.sub.4 can be used form an enhanced hexagonal ferrite material.