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 sintered body includes zirconia, iron, cobalt and titanium, in which a total iron and cobalt content is more than 0.1 mass % and less than 3 mass % and a titanium content is more than 3 mass %.

The MnZn ferrite material includes principal components and auxiliary components, where the principal components include: 52.5 mol % to 53.8 mol % of Fe.sub.2O.sub.3, 8.8 mol % to 12 mol % of ZnO, and the balance of MnO; the auxiliary components include: 0.35 wt % to 0.5 wt % of Co.sub.2O.sub.3, 0.03 wt % to 0.08 wt % of CaSiO.sub.3, 0.01 wt % to 0.04 wt % of Nb.sub.2O.sub.5, and 0.05 wt % to 0.12 wt % of TiO.sub.2 and RE elemental components; the RE elemental components include one or more from the group consisting of 0 wt % to 0.04 wt % of Gd.sub.2O.sub.3, 0 wt % to 0.02 wt % of HO.sub.2O.sub.3, and 0 wt % to 0.03 wt % of Ce.sub.2O.sub.3; the auxiliary components are all represented by a mass percentage relative to a total mass of the Fe.sub.2O.sub.3, the MnO, and the ZnO.

Embodiments disclosed herein relate to using cobalt (Co) to fine tune the magnetic properties, such as permeability and magnetic loss, of nickel-zinc ferrites to improve the material performance in electronic applications. The method comprises replacing nickel (Ni) with sufficient Co.sup.+2 such that the relaxation peak associated with the Co.sup.+2 substitution and the relaxation peak associated with the nickel to zinc (Ni/Zn) ratio are into near coincidence. When the relaxation peaks overlap, the material permeability can be substantially maximized and magnetic loss substantially minimized. The resulting materials are useful and provide superior performance particularly for devices operating at the 13.56 MHz ISM band.

Disclosed herein are doped perovskite oxides. The doped perovskite oxides may be used as a cathode material in an electrochemical cell to electrochemically generate ammonia from N.sub.2. The doped perovskite oxides may be combined with nitride compounds, for instance iron nitride, to further increase the efficiency of the ammonia production.

Provided is a ferrite sintered magnet including a ferrite phase having a magnetoplumbite-type crystal structure. x, y, and m satisfy the following Equations (1), (2), and (3) when composition of the ferrite sintered magnet is represented by R.sub.1-xA.sub.xFe.sub.m-yCo.sub.y, where R denotes at least one kind of element selected from rare earth elements including Y and A denotes Ca or Ca and elements including at least one kind selected from Sr or Ba. The content of B in the ferrite sintered magnet is from 0.1% to 0.6% by mass in terms of B.sub.2O.sub.3.

0.2≤x≤0.8  (1)

0.1≤y≤0.65  (2)

3≤m≤14  (3)

Provided is a red mud-based composite calcium ferrite and a preparation method and use thereof. The preparation method of the red mud-based composite calcium ferrite includes the following steps: mixing red mud and a calcium source, and roasting an obtained mixture in an oxygen-containing atmosphere to obtain the red mud-based composite calcium ferrite; where the calcium source is selected from the group consisting of lime and calcium carbonate. In the present disclosure, the composite calcium ferrite is prepared using a solid waste red mud, with a greatly reduced cost of raw materials; on the other hand, compared with traditional calcium ferrite, the composite calcium ferrite mainly has phase structures of CaFe.sub.2O.sub.4, Ca.sub.2FeAlO.sub.5, and Ca.sub.2Fe.sub.2O.sub.5. Therefore, the composite calcium ferrite has a lower melting point, a higher lime dissolution efficiency, and better fluxing and dephosphorization effects during primary smelting and refining of molten steel, and has broad prospects for use in industry.

A refractory article includes a body including a ceramic having an aluminosilicate present in an amount of at least 70 wt % and not greater than 99 wt % for a total weight of the body, and the body further includes a dopant including a Mg-containing oxide compound and a Fe-containing oxide compound, and the dopant is present in an amount within a range including at least 1 wt % and not greater than 12 wt %.

Provided is a ferrite sintered magnet including a ferrite phase having a magnetoplumbite-type crystal structure. x, y, and m satisfy the following Equations (1), (2), and (3) when composition of the ferrite sintered magnet is represented by R.sub.1-xA.sub.xFe.sub.m-yCo.sub.y, where R denotes at least one kind of element selected from rare earth elements including Y and A denotes Ca or Ca and elements including at least one kind selected from Sr or Ba. The content of B in the ferrite sintered magnet is from 0.1% to 0.6% by mass in terms of B.sub.2O.sub.3.
0.2≤x≤0.8  (1)
0.1≤y≤0.65  (2)
3≤m<14  (3)

In an aspect, an M-type ferrite, comprises oxides of Me, Me′, Me″, Co, Ti, and Fe; wherein Me is 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 Mg or Ca. In another aspect, a method of making an M-type ferrite comprises milling ferrite precursor compounds comprising oxides of at least Co, Fe, Ti, 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 Mg or Ca; and calcining the oxide mixture in an oxygen or air atmosphere to form the M-type ferrite.