Disclosed herein are embodiments of modified z-type hexagonal ferrite materials having improved properties that are advantageous for radiofrequency applications, in particular high frequency ranges for antennas and other devices. Atomic substitution of strontium, aluminum, potassium, and trivalent ions can be used to replace certain atoms in the ferrite crystal structure to improve loss factor at high frequencies.

A sintered ferrite magnet comprising main phases of ferrite having a hexagonal M-type magnetoplumbite structure, first grain boundary phases existing between two main phases, and second grain boundary phases existing among three or more main phases, the second grain boundary phases being dispersed in its arbitrary cross section, and the second grain boundary phases having an average area of less than 0.2 m.sup.2, are produced by calcining, pulverizing, molding and sintering raw material powders having the general formula of Ca.sub.1-x-yLa.sub.xA.sub.yFe.sub.2n-zCo.sub.z, wherein 1xy, x, y and z and n representing a molar ratio are in desired ranges; 1.8% or less by mass of SiO.sub.2 and 2% or less by mass (as CaO) of CaCO.sub.3 being added to a calcined body after calcining and before molding; and the sintering step being conducted with a temperature-elevating speed of 1-4 C./minute in a range from 1100 C. to a sintering temperature, and a temperature-lowering speed of 6 C./minute or more in a range from the sintering temperature to 1100 C.

An oxide ceramic expressed by the general formula Sr.sub.2-xBa.sub.xCo.sub.2-yMg.sub.yFe.sub.12-zAl.sub.zO.sub.22, where 0.7x1.3, 0<y0.8, and 0.8z1.2.

A fuel cell comprises an anode, a cathode, a solid electrolyte layer, and a current collecting member. The cathode contains a perovskite composite oxide as a main component and contains a compound that includes at least one of S and Cr as a secondary component. The cathode has a surface facing the current collecting member. The surface of the cathode includes a first region that is electrically connected to the current collecting member and a second region that is separated from the current collecting member. The first region and the second region respectively contain a main phase that is configured from a perovskite composite oxide and a secondary phase that is configured from the compound. The occupied surface area ratio of the secondary phase in the first region is greater than the occupied surface area ratio of the secondary phase in the second region.

A fuel cell comprises an anode, a cathode, and a solid electrolyte layer disposed between the anode and the cathode. The cathode includes a perovskite oxide as a main component. The perovskite oxide is expressed by the general formula ABO.sub.3 and includes at least one of La and Sr at the A site. The cathode includes a surface region that is within 5 micrometers from the surface opposite the solid electrolyte layer. The surface region contains a main phase configured by the perovskite oxide and a secondary phase that is configured by strontium oxide. The occupied surface area ratio of the secondary phase in a cross section of the surface region is greater than or equal to 0.05% to less than or equal to 3%.

In an aspect, a Co.sub.2Z-type ferrite comprises oxides of at least Me, Co, Mo, Li, and Fe; wherein Me is at least one of Ba or Sr. In another aspect, the Co.sub.2Z-type ferrite comprises a Z-type hexaferrite an amount of lithium molybdate. In another aspect, the Co.sub.2Z-type ferrite has a formula Li.sub.2MoO.sub.4.Math.Ba.sub.xSr.sub.3-xCo.sub.2+yzMe.sub.yMe.sub.zFe.sub.24-2y-mO.sub.41, wherein Me is at least one of Ti, Mo, Ru, Ir, Zr, or Sn; Me is at least one of Zn, Mn, or Mg; x is 0 to 3; y is 0 to 1.8; z is 0 to 1.8; and m is 4 to 4. In yet another aspect, a method of making a Co.sub.2Z-type ferrite comprises milling an initial Co.sub.2Z-type ferrite and Li.sub.2MoO.sub.4 to form a mixed ferrite; and calcining the mixed ferrite to form the Co.sub.2Z-type ferrite.

A ferrite magnet includes: a hexagonal ferrite main phase; and a second phase. The second phase is an oxide phase containing: an element A which is at least one selected from the group consisting of Ca, Sr, Ba, Bi, and rare earth elements; a transition metal element T including at least Fe; and an element G which is at least one selected from the group consisting of Si, Al, B, F, K, Na, Li, P, and S. When the total number of atoms of the element A, the transition metal element T, and the element G in the second phase is set to 100 at %, the element A occupies 30 to 80 at %, the element G occupies 15 to 40 at %, and the transition metal element T occupies less than 4 at %.

A solid ionic conducting material for use in an electrochemical device comprises an oxyhydroxide or hydrated oxide derived from of an oxide with a perovskite, Brownmillerite, layered oxide, and/or K.sub.4CdCl.sub.6 structure, the elemental composition of the initial oxide being selected to provide suitable conduction properties for the derived anhydrous or hydrated oxyhydroxide or hydrated oxide. A method of making such a solid ionic conducting material, including treatment with water, and an electrochemical device incorporating such a solid ionic conducting material (optionally as an electrolyte) are also disclosed.

In an aspect, an M-type ferrite comprises an element Me comprising at least one of Ba, Sr, or Pb; an element Me comprising at least one of Ti, Zr, Ru, or Ir; and an element Me comprising at least one of In or Sc. In another aspect, a method of making the M-type ferrite can comprise milling ferrite precursor compounds comprising oxides of at least Co, Fe, Me, Me, and Me to form an oxide mixture; wherein Me comprises at least one of Ba, Sr, or Pb; Me is at least one of Ti, Zr, Ru, or Ir; and Me is at least one of In or Sc; and calcining the oxide mixture in an oxygen or air atmosphere to form the ferrite.

The present disclosure relates to the technical field of electronic materials, and in particular to a low-temperature sintered high-dielectric constant gyromagnetic ferrite material and a preparation method therefor. The low-temperature sintered high-dielectric constant gyromagnetic ferrite material has the molecular formula of Bi.sub.1.45Ti.sub.0.1Y.sub.1.55-2x-yCa.sub.2x+yV.sub.xZr.sub.yF-0.1Fe.sub.5-y-xO.sub.12, wherein x is 0.6-0.65, y is 0.25-0.35, and 1.55-2x-y is 0. The preparation method provided by the present disclosure not only can realize low-temperature sintering at 900 C., but also can realize good co-firing compatibility with a silver electrode of a low temperature co-fired ceramics (LTCC) process.