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.

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.

A ferrite composition having a formula of Ba.sub.xNi.sub.2-yCu.sub.yTi.sub.3Fe.sub.zO.sub.31, wherein 4.5?x?5.5 0<y<2 or 0.05?y?1.5, and 11?z?13.

A radio wave-absorbing laminate film in which both the top surface and the bottom surface have superior transmission attenuation properties and reflection attenuation capabilities in extremely high-frequency wave bands and higher, and which exhibits excellent radio wave absorption properties even when extremely thin; a production method for the film; and an element containing the film. A radio wave-absorbing laminate film having radio wave-absorbing layers, the radio wave-absorbing laminate film including a center layer, two substrate layers, and two radio wave-absorbing layers, the center layer containing at least one metal layer, and the two substrate layers being laminated on both surfaces of the center layer. With regard to each of the two substrate layers, the radio wave-absorbing layer is laminated on the surface opposite to the center layer, and, the two substrate layers are the same or different, the two radio wave-absorbing layers are the same or different, and at least one of the radio wave-absorbing layers contains a magnetic body.

A NiHf- or NiTi-doped Co.sub.2Y-type ferrite, having a formula of

Ba.sub.n-xSr.sub.xCo.sub.2-yCu.sub.yNi.sub.zHf.sub.zFe.sub.(m-2z)O.sub.22

or

Ba.sub.n-xSr.sub.xCo.sub.2-yCu.sub.yNi.sub.zTi.sub.zFe.sub.(m-2z)O.sub.22

wherein 2?n?2.4. 0?x?1, 0.1?y?1, 0<z?2, and 10?m?13.

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.

The magnetic tape includes: a non-magnetic support; a non-magnetic layer including non-magnetic powder and a binding agent on the non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic layer, in which a total thickness of the non-magnetic layer and the magnetic layer is equal to or smaller than 0.60 ?m, the magnetic layer has a servo pattern, the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, an intensity ratio of a peak intensity of a diffraction peak of a (110) plane with respect to a peak intensity of a diffraction peak of a (114) plane of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, and a vertical direction squareness ratio of the magnetic tape is 0.65 to 1.00, and a magnetic tape device including this magnetic tape.

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 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.