An iron-based oxide magnetic particle powder has a narrow particle size distribution a small content of fine particles that do not contribute to magnetic recording characteristics, and a narrow coercive force distribution, to enhance magnetic recording medium density. Neutralizing an aqueous solution containing a trivalent iron ion and an ion of the metal substituting a part of the Fe sites by adding an alkali to make pH of 1.5 or more and 2.5 or less, adding a hydroxycarboxylic acid, and further neutralizing by adding an alkali to make pH of 8.0 or more and 9.0 or less are performed at 5° C. or more and 25° C. or less. A formed iron oxyhydroxide precipitate containing the substituting metal element is rinsed with water, then coated with silicon oxide, and then heated thereby providing e-type iron-based oxide magnetic particle powder. The rinsed precipitate may be subjected to a hydrothermal treatment.

The present invention relates to a method of preparing an iron-chromium oxide using an ion-exchange resin. Moreover, the present invention relates to a method of preparing an iron-chromium oxide that can be used as a cathode material for lithium-ion batteries. According to one aspect of the present invention, it has the effect of providing a cathode material for lithium-ion batteries with a high capacitance, while exhibiting a voltage similar to that of a transition-metal oxide (2-4.5 V vs Li.sup.+/Li).

This ferrite magnet has a magnetoplumbite structure and is characterized in that, when representing the composition ratios of the total of each metal element A, R, Fe and Me with expression (1) A.sub.1-xR.sub.x(Fe.sub.12-yMe.sub.y).sub.z, the Fe.sup.2+ content (m) in the ferrite magnet is greater than 0.1 mass % and less than 5.4 mass % (in expression (1), A is at least one element selected from Sr, Ba, Ca and Pb; R is at least one element selected from the rare-earth elements (including Y) and Bi, and includes at least La, and Me is Co, or Co and Zn). The invention makes it possible to achieve a ferrite magnet with increased Br.

A core-shell particle includes: a core including an iron oxyhydroxide compound represented by Formula A.sup.3.sub.a3Fe.sub.1−a3OOH (in which A.sup.3 represents at least one metal element other than Fe, and a3 satisfies 0<a3<1) or at least one iron oxide compound selected from the group consisting of Fe.sub.2O.sub.3, a compound represented by Formula A.sup.1.sub.a1Fe.sub.2−a1O.sub.3 (in which A.sup.1 represents at least one metal element other than Fe, and a1 satisfies 0<a1<2), Fe.sub.3O.sub.4, and a compound represented by Formula A.sup.2.sub.a2Fe.sub.3−a2O.sub.4 (in which A.sup.2 represents at least one metal element other than Fe, and a2 satisfies 0<a2<2); and a shell which covers the core and includes a polycondensate of a metal alkoxide.

A hexagonal strontium ferrite powder, in which an average particle size is 10.0 to 25.0 nm, a content of one or more kinds of atom selected from the group consisting of a gallium atom, a scandium atom, an indium atom, and an antimony atom is 1.0 to 15.0 atom % with respect to 100.0 atom % of an iron atom, and a coercivity Hc is greater than 2,000 Oe and smaller than 4.000 Oe. A magnetic recording medium including: a non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, in which the ferromagnetic powder is the hexagonal strontium ferrite powder. A magnetic recording and reproducing apparatus including this magnetic recording medium.

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.

Described herein are chemically assembled nanoparticles of a multiferroic material embedded into a conductive (e.g., metal-organic) framework host that allows for tunable qubit spacing and overall architecture. In certain aspects, the composites described herein can function as solid-state qubits. In other aspects, the composites described herein can be implemented in systems used in quantum information processing (QIP). In other aspects, the composites described herein can be used as a quantum sensor.

The invention relates to active electrode materials and to methods for the manufacture of active electrode materials. Such materials are of interest as active electrode materials in lithium-ion or sodium-ion batteries. The invention provides an active electrode material expressed by the general formula [M][Nb].sub.y[O].sub.z; wherein the active electrode material is oxygen deficient; wherein M consists of one of Mg, Cr, W, Mo, Cu, Ga, Ge, Ca, K, Ni, Co, Al, Sn, Mn, Ce, Sb, Y, La, Hf, Ta, Zn, In, or Cd; y satisfies 0.5≤y≤49; and z satisfies 4≤z≤124.

The present invention relates to a process for preparing a rodlike magnetic ferroferric oxide (Fe.sub.3O.sub.4) material and use thereof. The preparation includes the following steps: step 1: magnetic Fe3O4 nanoparticle preparation; and step 2: self-assembly of magnetic Fe3O4@SiO2 nanoparticles into a rodlike magnetic material. When in use, the rodlike magnetic Fe.sub.3O.sub.4 material prepared by the process according to claim 1 is used in micro- and nano-motors, which can implement rotation and deflection in an external magnetic field. The present invention provides a process for preparing a rodlike magnetic Fe.sub.3O.sub.4 material. The rodlike magnetic ferroferric oxide material prepared by the process is suitable for mass production on an industrial scale, featuring identifiable direction of the magnetic moment, strong magnetism, good magnetic response, simple process, and low cost.

A grain-oriented M-type hexagonal ferrite has the formula MeFe.sub.12O.sub.19, and a dopant effective to provide planar magnetic anisotropy and magnetization in a c-plane, or a cone anisotropy, in the hexagonal crystallographic structure wherein Me is Sr.sup.+, Ba.sup.2+ or Pb.sup.2+, and wherein greater than 30%, preferably greater than 80%, of c-axes of the ferrite grains are aligned perpendicular to the c-plane.