Magnetic beads comprise a plurality of magnetic nanoparticles, dispersed in a non-magnetic matrix. The magnetic beads have an average particle size of 0.1 μm to 100 μm. The matrix may comprise an inorganic metal oxide or a polymer. The magnetic beads have a specific surface area of at least 40 m.sup.2/g.

The present invention provides a method for preparing iron oxide magnetic particles and iron oxide magnetic particles prepared thereby, wherein the method includes (a) synthesizing a complex by reacting iron and one or more compounds selected from the group consisting of an aliphatic hydrocarbonate having 4 to 25 carbon atoms and an amine compound, (b) synthesizing an iron oxide crystal nucleus by mixing the complex with a mixture of an unsaturated aliphatic hydrocarbon-based compound having 4 to 25 carbon atoms and an ether-based compound, and (c) forming a shell by mixing the iron oxide crystal nucleus and an MXn compound with a mixture of an unsaturated aliphatic hydrocarbon-based compound having 4 to 25 carbon atoms and an ether-based compound, wherein M is a heavy atom element, X is a halogen element, and n is an integer of 1 to 6.

The present invention provides iron oxide magnetic particles including an iron oxide and MX.sub.n, wherein M includes one or more selected from the group consisting of Cu, Sn, Pb, Mn, Ir, Pt, Rh, Re, Ag, Au, Pd, and Os, X includes one or more selected from the group consisting of F, Cl, Br, and I, and n is an integer of 1 to 6.

An organometallic compound, which enables thin-film deposition through vapor deposition, and particularly to a Co or Fe precursor, which is suitable for use in atomic layer deposition or chemical vapor deposition, and a method of preparing the same.

[Problem] To provide a method for producing iron based oxide magnetic powder that has a narrow particle size distribution and a small content of fine particles that do not contribute to the magnetic recording characteristics, and consequently has a narrow coercive force distribution and is suitable for the enhancement of the recording density of the magnetic recording medium. [Solution] ε-Type iron based oxide magnetic powder is obtained by a wet method, then a tetraalkylammonium salt as a surface modifier is added to a slurry containing the magnetic powder to make a concentration of 0.009 mol/kg or more and 1.0 mol/kg or less, and simultaneously to make pH of 11 or more and 14 or less, and the slurry is subjected to a dispersion treatment and then classified, so as to provide iron based oxide magnetic powder having a narrow particle size distribution and a narrow coercive force distribution.

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.

An anode material for a secondary battery is provided. The anode material for the secondary battery includes a metal oxide containing four or more than four elements, or an oxide mixture containing four or more than four elements. The metal oxide includes cobalt-copper-tin oxide, silicon-tin-iron oxide, copper-manganese-silicon oxide, tin-manganese-nickel oxide, manganese-copper-nickel oxide, or nickel-copper-tin oxide. The oxide mixture includes the oxide mixture containing cobalt, copper and tin, the oxide mixture containing silicon, tin and iron, the oxide mixture containing copper, manganese and silicon, the oxide mixture containing tin, manganese and nickel, the oxide mixture containing manganese, copper and nickel, or the oxide mixture containing nickel, copper and tin.

The present invention provides a powdered ferrite having high dispersibility in a resin and high electromagnetic shielding characteristics. The powdered ferrite comprises platy ferrite particles having a spinel crystal structure. The powdered ferrite comprises at least 50 number % platy ferrite particles each having at least one protrusion on a surface of the particle, and the protrusion has a shape selected from the group consisting of a rectangular pyramid, a truncated rectangular pyramid, an elongated rectangular pyramid, and combinations thereof.

A radio wave absorber includes a base member, and a radio wave absorption film formed on the base member. The radio wave absorption film includes at least MTC-substituted ε-Fe.sub.2O.sub.3 and black titanium oxide. The MTC-substituted ε-Fe.sub.2O.sub.3 is a crystal belonging to the same space group as an ε-Fe.sub.2O.sub.3 crystal and expressed by ε-M.sub.xTi.sub.yCo.sub.yFe.sub.2−2y−xO.sub.3 where M is at least one element selected from the group consisting of Ga, In, Al, and Rh, 0<x<1, and 0<y<1.

It has been found, that when co-absorbing substances are added to intrinsic laser-absorbing bismuthoxide, the marking performance with a Nd.YAG-laser is improved or at least kept at the same level by reducing the costs. It is suspected, that the co-absorbing additive is not simply adding a contrast to the polymer by carbonizing the surrounding polymer but helping the bismuthoxide to couple the laser radiation and to ease the color change of this additive. This so found effect helps to cheapen the replacement of antimony trioxide and therewith have a safer and more sustainable solution for the current and future technology of laser marking.