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.

A radio wave absorber includes hexagonal ferrite particles and a holding material-filled with the hexagonal ferrite particles. The hexagonal ferrite particles include first particles and second particles that are larger than the first particles in particle size.

Provided are a ferrite powder that suppresses decreases in saturation magnetization and decreases in filler filling ratio and also suppresses inhibition of resin curing, and a method for producing the same. A ferrite powder composed of spherical ferrite particles, wherein the ferrite powder contains iron (Fe) 54.0-70.0 mass % and manganese (Mn) 3.5-18.5 mass %, has an average volume particle size of 2.0-20.0 μm, and has a carbon content of 0.100 mass % or lower.

In an aspect, a ferrite composition can comprise a SbCo—M-type ferrite having the formula: Me.sub.1-xSb.sub.xCo.sub.y+xM′.sub.yFe.sub.12-x-2yO.sub.19, wherein Me is at least one of Sr, Pb, or Ba; M′ is at least one of Ti, Zr, Ru, or Ir; x is 0.001 to 0.3; and y is 0.8 to 1.3. In another aspect, a method of making the ferrite composition comprises mixing ferrite precursor compounds comprising Me, Fe, Sb, Co, and M; and sintering the ferrite precursor compounds in an oxygen atmosphere to form the SbCo—M-type ferrite. In yet another aspect, a composite comprises the ferrite composition and a polymer. In still another aspect, an article comprises the ferrite composition.

An inductor core includes a magnetic main body having a pillar shape and comprised of a magnetic material. The magnetic main body includes an inclined portion including an inclined surface that constitutes an outer circumferential surface of a truncated cone having an outer diameter increasing from one end toward the other end; and a straight body portion that is coaxial with the inclined portion and includes an outer peripheral surface that constitutes an outer circumferential surface of a cylindrical column body extending from the other end toward the one end, the straight body portion being connected to the inclined portion. An arithmetic mean roughness Ra of an outer peripheral surface of the straight body portion located at or around the other end is smaller than an arithmetic mean roughness Ra of an outer peripheral surface of the straight body portion that is disposed at or around the inclined portion.

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.Ba.sub.xSr.sub.3-xCo.sub.2+y−zMe′.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.

Provided is an electromagnetic-wave absorber composition and an electromagnetic-wave absorber that can favorably absorb a plurality of electromagnetic waves of different frequencies in a high frequency band in or above the millimeter-wave band. The electromagnetic-wave absorber composition includes a magnetic iron oxide that magnetically resonates at a high frequency in or above the millimeter-wave band and a resin binder. The electromagnetic-wave absorber composition has two or more extrema separated from each other on a differential curve obtained by differentiating a magnetic property hysteresis loop at an applied magnetic field intensity of from 16 kOe to −16 kOe. The electromagnetic-wave absorber includes an electromagnetic-wave absorbing layer formed of the above-described electromagnetic-wave absorber composition.

Provided is an electromagnetic-wave absorber composition and an electromagnetic-wave absorber that can favorably absorb a plurality of electromagnetic waves of different frequencies in a high frequency band in or above the millimeter-wave band. The electromagnetic-wave absorber composition includes a magnetic iron oxide that magnetically resonates at a high frequency in or above the millimeter-wave band and a resin binder. The electromagnetic-wave absorber composition has two or more extrema separated from each other on a differential curve obtained by differentiating a magnetic property hysteresis loop at an applied magnetic field intensity of from 16 kOe to −16 kOe. The electromagnetic-wave absorber includes an electromagnetic-wave absorbing layer formed of the above-described electromagnetic-wave absorber composition.

A magnetoelectric multiferroic nanocomposite. The nanocomposite comprises a ferroelectric perovskite oxide and a rare-earth substituted mixed ternary transition metal ferrite of the formula A.sub.1−xB.sub.xR.sub.yFe.sub.2−yO.sub.4. The nanocomposite has a high dielectric constant, low dielectric loss, both stable over a wide frequency range. These properties may make the nanocomposite desirable for applications in microelectronic devices, sensors and antennas.

A magnetic fiber comprises a core comprising a spinel ferrite of formula Me.sub.1-xM.sub.xFe.sub.yO.sub.4, wherein Me is Mg, Mn, Fe, Co, Ni, Cu, Zn, or a combination thereof, x=0 to 0.25, and y=1.5 to 2.5, wherein the core is solid or at least partially hollow; and a shell at least partially surrounding the core, and comprising a Me.sub.1-xM.sub.xFe.sub.y alloy, wherein when the core is solid with Me=Ni and x=0 the magnetic fiber has a diameter of greater than 0.3 micrometer. A magneto-dielectric material having a magnetic loss tangent of less than or equal to 0.03 at 1 GHz comprises a polymer matrix; and a plurality of the magnetic fibers.