One object is to increase the filling factor of magnetic particles and increase the evenness of distribution of the magnetic particles in a magnetic main body of a coil component. A coil component includes: a magnetic main body containing a resin and magnetic particles; and a coil conductor embedded in the magnetic main body. The magnetic particles include large-sized magnetic particles, middle-sized magnetic particles, and small-sized magnetic particles. The proportion of the volume of the large-sized magnetic particles to the total volume of all the magnetic particles is 70 vol % to 85 vol %, the proportion of the volume of the middle-sized magnetic particles to the total volume is 2 vol % to 28 vol %, and the proportion of the volume of the small-sized magnetic particles to the total volume is 2 vol % to 28 vol %. The particle size distribution of the small-sized magnetic particles overlaps that of the middle-sized magnetic particles.

One object is to increase the filling factor of magnetic particles and increase the evenness of distribution of the magnetic particles in a magnetic main body of a coil component. A coil component includes: a magnetic main body containing a resin and magnetic particles; and a coil conductor embedded in the magnetic main body. The magnetic particles include large-sized magnetic particles, middle-sized magnetic particles, and small-sized magnetic particles. The proportion of the volume of the large-sized magnetic particles to the total volume of all the magnetic particles is 70 vol % to 85 vol %, the proportion of the volume of the middle-sized magnetic particles to the total volume is 2 vol % to 28 vol %, and the proportion of the volume of the small-sized magnetic particles to the total volume is 2 vol % to 28 vol %. The particle size distribution of the small-sized magnetic particles overlaps that of the middle-sized magnetic particles.

In an aspect, a ferrite composition comprises a Ru—Co.sub.2Z ferrite having the formula: (Ba.sub.3-xM.sub.x)Co.sub.2(M′Ru).sub.yFe.sub.24-2y-zO.sub.41, wherein M is at least one of Sr, Pb, or Ca; M′ is at least one of Co, Zn, Mg, or Cu; x is 1 to 3; y is greater than 0 to 2; and z is −4 to 4. In another aspect, an article comprises the ferrite composition. In yet another aspect, method of making the ferrite composition comprises mixing ferrite precursor compounds comprising Fe, Ba, Co, and Ru; and sintering the ferrite precursor compounds in an oxygen atmosphere to form the Ru—Co.sub.2Z ferrite.

In an aspect, a composition comprises a plurality of magnetic particles. The magnetic particles each independently comprise a nickel ferrite core having the formula Ni.sub.1−xM.sub.xPe.sub.2+yO.sub.4, wherein M is at least one of Zn, Mg, Co, Cu, Al, Mn, or Cr; x is 0 to 0.95, and y=−0.5 to 0.5; and an iron nickel shell at least partially surrounding the core, wherein the iron nickel shell comprises iron, nickel, and optionally M. In another aspect, a method of forming the magnetic particles comprises heat treating a plurality of nickel ferrite particles in a hydrogen atmosphere to form the plurality of magnetic particles having the iron nickel shell on the nickel ferrite core. In yet another aspect, a composite can comprise the magnetic particles and a polymer.

To provide a ferrite sintered magnet having a high residual magnetic flux density (Br) and a high coercive force (HcJ), and also able to produce at a low cost. The ferrite sintered magnet includes a hexagonal M-type ferrite including A, R, Fe, and Co in an atomic ratio of A.sub.1-xR.sub.x(Fe.sub.12-yCo.sub.y).sub.zO.sub.19. A is at least one selected from Sr, Ba, and Pb. R is La only or La and at least one selected from rare earth elements. 0.13≤x≤0.23, 10.80≤(12−y)z≤12.10, and 0.13≤yz≤0.20 are satisfied.

A ferrite sintered magnet including ferrite grains having a hexagonal crystal structure. The ferrite grains satisfy 0.56≤W≤0.68 where W is an average value of circularities of the ferrite grains in a cross section parallel to an axis of easy magnetization.

Disclosed herein are ceramic materials, such as bismuth substituted garnets, which can have high curie temperatures and high dielectric constants. In certain implementations, indium can be incorporated into the ceramic to improve certain properties and to avoid calcium compensation. The ceramic materials disclosed herein can be particular advantageous for below resonance applications.

A soft magnetic composition that includes an oxide containing a W-type hexagonal ferrite having a compositional formula of ACaMe.sub.2Fe.sub.16O.sub.27 as a main phase, wherein A is one or more selected from Ba, Sr, Na, K, La, and Bi at 4.7 mol % to 5.8 mol %; Me is one or more selected from Co, Cu, Mg, Mn, Ni, and Zn at 9.4 mol % to 18.1 mol %, the Ca is 0.2 mol % to 5.0 mol %, the Fe is 67.4 mol % to 84.5 mol %, and the soft magnetic composition has a coercivity Hcj of 100 kA/m or less.

A soft magnetic composition that includes an oxide containing a W-type hexagonal ferrite having a compositional formula of ACaMe.sub.2Fe.sub.16O.sub.27 as a main phase, wherein A is one or more selected from Ba, Sr, Na, K, La, and Bi at 4.7 mol % to 5.8 mol %; Me is one or more selected from Co, Cu, Mg, Mn, Ni, and Zn at 9.4 mol % to 18.1 mol %, the Ca is 0.2 mol % to 5.0 mol %, the Fe is 67.4 mol % to 84.5 mol %, and the soft magnetic composition has a coercivity Hcj of 100 kA/m or less.

To provide a ferrite sintered magnet having a high residual magnetic flux density (Br), a high coercive force (HcJ), a good production stability, and also able to produce at a low cost. The ferrite sintered magnet includes a hexagonal M-type ferrite including A, R, Fe, and Co in an atomic ratio of A.sub.1-xR.sub.x(Fe.sub.12-yCo.sub.y).sub.zO.sub.19. A is at least one selected from Sr, Ba, and Pb. R is La only or La and at least one selected from rare earth elements. 0.14≤x≤0.22, 11.60≤(12-y)z≤11.99, and 0.13≤yz≤0.17 are satisfied. 0.30≤Mc≤0.63 is satisfied in which Mc is CaO content (mass %) converted from a content of Ca included in the ferrite sintered magnet.