A magnetic refrigeration material includes an alloy represented by a composition formula of La(Fe, Si).sub.13H, and the alloy includes α-Fe by a weight ratio lower than 1 wt % and a plurality of pores so that a packing fraction of the alloy is within a range from 85% to 99%.

In various aspects, methods of making perovskite manganese oxide particles are provided as well as perovskite manganese oxide particles made therefrom. The perovskite manganese oxide particles exhibit a strong magnetocaloric effect, making them well suited for applications in power generation and magnetic refrigeration, especially at or near room temperature. The methods can include forming an aqueous mixture of (i) a low-molecular-weight polymeric polyalcohol gel precursor, (ii) a stoichiometric amount of metal salts or hydrates thereof, wherein the metal salts or hydrates thereof comprise at least a Manganese (Mn), and (iii) a polybasic carboxylic acid; polymerizing the aqueous mixture to form a gel containing perovskite manganese oxide nanoparticles entrapped therein; and calcining the gel to remove at least a portion of organic material in the gel and form the perovskite manganese oxide particles. Method and systems are also provided for power generation and magnetic refrigeration using the perovskite manganese oxide particles.

Disclosed herein is a composite particle comprising a first non-metallic particle in which is dispersed a second non-metallic particle, where the first non-metallic particle and the second non-metallic particle are inorganic; and where a chemical composition of the first non-metallic particle is different from a chemical composition of the second non-metallic particle; and where the first non-metallic particle and the second non-metallic particle are metal oxides, metal carbides, metal nitrides, metal borides, metal silicides, metal oxycarbides, metal oxynitrides, metal boronitrides, metal carbonitrides, metal borocarbides, or a combination thereof.

Disclosed herein is a composite particle comprising a first non-metallic particle in which is dispersed a second non-metallic particle, where the first non-metallic particle and the second non-metallic particle are inorganic; and where a chemical composition of the first non-metallic particle is different from a chemical composition of the second non-metallic particle; and where the first non-metallic particle and the second non-metallic particle are metal oxides, metal carbides, metal nitrides, metal borides, metal silicides, metal oxycarbides, metal oxynitrides, metal boronitrides, metal carbonitrides, metal borocarbides, or a combination thereof.

The invention includes miniature dots, miniature disks or miniature cylinders and methods of making the same by dispersing a particle in or on a dissolvable, meltable or etchable layer on a substrate, a portion of the particle exposed above a surface of the dissolvable, meltable or etchable layer; depositing a mask on the particles and the dissolvable substrate; removing the particles from the layer; etching an array of nanoholes in the substrate; depositing one or more metallic layers into the nanoholes to form an array of dots, disks or cylinders; and dissolving the dissolvable layer with a solvent to expose the dots, disks or cylinders. The dots, disks or cylinders can be included with two sets of microelectrodes for ultrahigh speed rotation of miniature motors, and/or can be designed with a magnetic configuration into miniature motors for uniform rotation speeds and prescribed angular displacement. The invention also includes modified diatom frustules, and miniature motors containing modified diatom frustules.

The invention includes miniature dots, miniature disks or miniature cylinders and methods of making the same by dispersing a particle in or on a dissolvable, meltable or etchable layer on a substrate, a portion of the particle exposed above a surface of the dissolvable, meltable or etchable layer; depositing a mask on the particles and the dissolvable substrate; removing the particles from the layer; etching an array of nanoholes in the substrate; depositing one or more metallic layers into the nanoholes to form an array of dots, disks or cylinders; and dissolving the dissolvable layer with a solvent to expose the dots, disks or cylinders. The dots, disks or cylinders can be included with two sets of microelectrodes for ultrahigh speed rotation of miniature motors, and/or can be designed with a magnetic configuration into miniature motors for uniform rotation speeds and prescribed angular displacement. The invention also includes modified diatom frustules, and miniature motors containing modified diatom frustules.

A laminated coil component that can use inexpensive copper as an internal conductor, and has excellent direct current superimposition characteristics is provided. In a laminated coil component including: a magnetic section including a ferrite material; a non-magnetic section including a non-magnetic ferrite material; and a coiled conductor section containing copper as a main component embedded inside the magnetic section and the non-magnetic section, the non-magnetic section contains at least Fe, Mn and Zn, and optionally Cu. The non-magnetic section has a Fe content of 40.0 mol % to 48.5 mol % in terms of Fe.sub.2O.sub.3, a Mn content of 0.5 mol % to 9 mol % in terms of Mn.sub.2O.sub.3 and a Cu content of 8 mol % or less in terms of CuO.

A laminated coil component that can use inexpensive copper as an internal conductor, and has excellent direct current superimposition characteristics is provided. In a laminated coil component including: a magnetic section including a ferrite material; a non-magnetic section including a non-magnetic ferrite material; and a coiled conductor section containing copper as a main component embedded inside the magnetic section and the non-magnetic section, the non-magnetic section contains at least Fe, Mn and Zn, and optionally Cu. The non-magnetic section has a Fe content of 40.0 mol % to 48.5 mol % in terms of Fe.sub.2O.sub.3, a Mn content of 0.5 mol % to 9 mol % in terms of Mn.sub.2O.sub.3 and a Cu content of 8 mol % or less in terms of CuO.

Provided is a magnetic refrigeration material represented by the formula La.sub.1-fRE.sub.f(Fe.sub.1-a-b-c-d-eSi.sub.aCo.sub.bX.sub.cY.sub.dZ.sub.e).sub.13 (RE: at least one of rare earth elements including Sc and Y and excluding La; X: Ga and/or Al; Y: at least one of Ge, Sn, B, and C; Z: at least one of Ti, V, Cr, Mn, Ni, Cu, Zn, and Zr; 0.03≦a≦0.17, 0.003≦b≦0.06, 0.02≦c≦0.10, 0≦d≦0.04, 0≦e≦0.04, 0≦f≦0.50), and having an average crystal grain size of not smaller than 0.01 μm and not larger than 3 μm, a Curie temperature of not lower than 250 K, and the maximum (−ΔS.sub.max) of magnetic entropy change (−ΔS.sub.M) when subjected to a field change up to 2 Tesla is not less than 5 J/kgK.

A strip cast alloy containing Nd in excess of the stoichiometry of Nd.sub.2Fe.sub.14B is subjected to HDDR treatment and diffusion treatment, yielding microcrystalline alloy powder in which major phase crystal grains with a size of 0.1-1 μm are surrounded by Nd-rich grain boundary phase with a width of 2-10 nm. The powder is finely pulverized, compacted, and sintered, yielding a sintered magnet having a high coercivity.