An aspect of the present invention relates to A method of manufacturing hexagonal ferrite powder, which comprises heating to equal to or higher than 300 C. and pressurizing to equal to or higher than 20 MPa a hexagonal ferrite precursor-containing water-based solution, to convert the precursor to hexagonal ferrite, wherein the water-based solution comprises at least a reducing compound selected from the group consisting of a reducing inorganic compound and a reducing organic compound that have a reducing property and exist as a solid or a liquid at ordinary temperature and ordinary pressure, as well as, when the reducing compound is a reducing inorganic compound, the water-based solution further comprises an organic compound.

A method is provided for making a magnesium(Mg)-iron(Fe) complex oxide. The MgFe complex oxide is used for separating and purifying carbon dioxide (CO.sub.2). The present invention solves the problem of using iron ore in chemical looping combustion. The present invention comprises the following steps: At first, iron ore and magnesium nitrate (Mg(NO.sub.3).sub.2.6H.sub.2O) are impregnated for reaction. After sieving within a fixed range of size, calcination is processed to obtain the MgFe complex oxide. Not only the problem of using iron ore in chemical combustion loop is effectively solved; but also the whole procedure can be looped for a long time with a high CO.sub.2 conversion rate.

A ferrite powder for bonded magnets capable of producing a ferrite bonded magnet having a BH.sub.max value of 2.65 MGOe or more when molded in a magnetic field and a method for producing the same, and a ferrite bonded magnet using the same, wherein a compression density is 3.50 g/cm.sup.3 or more, and an average value of a (long axis length/short axis length) ratio of ferrite particles having a long axis length of 1.0 m or more is, 1.60 or less.

Preparation, characterization, and an electrochemical study of Mg0.1V2O5 prepared by a novel sol-gel method with no high-temperature post-processing are disclosed. Cyclic voltammetry showed the material to be quasi-reversible, with improved kinetics in an acetonitrile-, relative to a carbonate-, based electrolyte. Galvanostatic test data under a C/10 discharge showed a delivered capacity >250 mAh/g over several cycles. Based on these results, a magnesium anode battery, as disclosed, would yield an average operating voltage 3.2 Volts with an energy density 800 mWh/g for the cathode material, making the newly synthesized material a viable cathode material for secondary magnesium batteries.

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.

The method of manufacturing hexagonal ferrite powder includes preparing a hexagonal ferrite precursor by mixing an iron salt and a divalent metal salt in a water-based solution, and converting the hexagonal ferrite precursor into hexagonal ferrite within a reaction flow passage, within which a fluid flowing therein is subjected to heating and pressurizing, by continuously feeding a water-based solution containing the hexagonal ferrite precursor and gelatin to the reaction flow passage.

A carrier core material is represented by a composition formula M.sub.xFe.sub.3-xO.sub.4 (where M is Mn and/or Mg, and X is a total of Mn and Mg and is a substitution number of Fe by Mn and Mg, 0<X1), in which 5 to 20 number percent of bound particles in which 2 to 5 spherical particles are bound together are contained, and in which the absolute value of a difference between lattice constants before and after milling which are calculated from a peak position of plane indices in a powder X-ray diffraction pattern is equal to or less than 0.005. In this way, it is possible to increase the amount of toner supplied to a development region, and even when cracking or chipping occurs in the carrier core material, an image failure such as black spots or white spots is prevented from being generated.

A magnetic recording medium includes: a substrate; and a magnetic layer including a ferrimagnetic particle powder. A product (VSFD) of a particle volume V and a holding force distribution SFD of the ferrimagnetic particle is equal to or less than 2500 nm.sup.3.

A piezoelectric material that has good insulating properties and piezoelectricity and is free of lead and potassium and a piezoelectric element that uses the piezoelectric material are provided. The piezoelectric material contains copper and a perovskite-type metal oxide represented by general formula (1): (1?x){(Na.sub.yBa.sub.1?z)(Nb.sub.zTi.sub.1?z) O.sub.3}-xBiFeO.sub.3 (where 0<x?0.015, 0.80?y?0.95, and 0.85 ?z?0.95). In the piezoelectric material, 0.04 mol % or more and 2.00 mol % or less of Cu is contained relative to 1 mol of the perovskite-type metal oxide. Also provided is a piezoelectric element that includes a first electrode, a piezoelectric material, and a second electrode, in which the piezoelectric material described above is used as the piezoelectric material.

A Co.sub.2Z hexaferrite composition is provided containing molybdenum and one or both of barium and strontium, having the formula (Ba.sub.2Sr.sub.(3-Z)Co.sub.(2+X))Mo.sub.xFe.sub.(y-2x)O.sub.41 where x=0.01 to 0.20; y=20 to 24; and z=0 to 3. The composition can exhibit high permeabilities and equal or substantially equal values of permeability and permittivity while retaining low magnetic and dielectric loss tangents and loss factors. The composition is suitable for high frequency applications such as ultrahigh frequency and microwave antennas and other devices.