A nanogranular magnetic film includes a structure including first phases comprised of nano-domains dispersed in a second phase. The first phases include at least one selected from the group consisting of Fe, Co, and Ni. The second phase includes at least one selected from the group consisting of O, N, and F. A ratio of a volume of the first phases to a total volume of the first phases and the second phase is 65% or less. The nanogranular magnetic film has a porosity of 0.17 or more and 0.30 or less.

The iron alloy particle is a particle including an iron alloy. The particle includes multiple mixed-phase particles, each including nanocrystals of 10 nm or more and 100 nm or less (i.e., from 10 nm to 100 nm) in crystallite size and an amorphous phase; and a grain boundary layer between the mixed-phase particles. Also, the iron alloy has a composition containing Fe, Si, P, B, C, and Cu.

The iron alloy particle is a particle including an iron alloy. The particle includes multiple mixed-phase particles, each including nanocrystals of 10 nm or more and 100 nm or less (i.e., from 10 nm to 100 nm) in crystallite size and an amorphous phase; and a grain boundary layer between the mixed-phase particles. Also, the iron alloy has a composition containing Fe, Si, P, B, C, and Cu.

A nanocrystalline magnetic conductive sheet for wireless charging and a preparation method therefor are provided. The nanocrystalline magnetic conductive sheet includes a composition of Fe.sub.(100-x-y-z-α-β-γ)M.sub.xCu.sub.yM′.sub.zSi.sub.αB.sub.βX.sub.γ, saturation magnetic induction is greater than or equal to 1.25T. The preparation method includes preparing an alloy with a preset composition of into an alloy strip with an initial state of amorphousness by a single roll rapid quenching method, annealing an amorphous alloy strip according to a preset annealing process, to obtain a nanocrystalline strip, performing a magnetic fragmentation process on the nanocrystalline strip, to obtain the nanocrystalline magnetic conductive sheet for wireless charging.

A nanocrystalline magnetic conductive sheet for wireless charging and a preparation method therefor are provided. The nanocrystalline magnetic conductive sheet includes a composition of Fe.sub.(100-x-y-z-α-β-γ)M.sub.xCu.sub.yM′.sub.zSi.sub.αB.sub.βX.sub.γ, saturation magnetic induction is greater than or equal to 1.25T. The preparation method includes preparing an alloy with a preset composition of into an alloy strip with an initial state of amorphousness by a single roll rapid quenching method, annealing an amorphous alloy strip according to a preset annealing process, to obtain a nanocrystalline strip, performing a magnetic fragmentation process on the nanocrystalline strip, to obtain the nanocrystalline magnetic conductive sheet for wireless charging.

Provided is a soft magnetic alloy including Fe as a main component, in which a slope of an approximate straight line, plotted between cumulative frequencies of 20 to 80% on Fe content in each grid of 80000 grids or more, each of which has 1 nm×1 nm×1 nm, is −0.1 to −0.4, provided that Fe content (atom %) of each grid is Y axis, and the cumulative frequencies (%) obtained in descending order of Fe content in each grid is X axis, and an amorphization ratio X is 85% or more.

Provided is a soft magnetic alloy including Fe as a main component, in which a slope of an approximate straight line, plotted between cumulative frequencies of 20 to 80% on Fe content in each grid of 80000 grids or more, each of which has 1 nm×1 nm×1 nm, is −0.1 to −0.4, provided that Fe content (atom %) of each grid is Y axis, and the cumulative frequencies (%) obtained in descending order of Fe content in each grid is X axis, and an amorphization ratio X is 85% or more.

A nanocrystalline alloy ribbon has an alloy composition represented by Fe.sub.balCu.sub.xB.sub.ySi.sub.zA.sub.aX.sub.b where 0.6≤x<1.2, 10≤y≤20, 0<z≥10, 10(y+z)24, 0≤a≤10, O≤b≤5, with the balance being Fe and incidental impurities, where A is an optional inclusion of at least one element selected from Ni, Mn, Co, V, Cr, Ti, Zr, Nb, Mo, Hf, Ta and W, and X is an optional inclusion of at least one element selected from Re, Y, Zn, As, In, Sn, and rare earth elements, all numbers being in atomic percent. The ribbon has a local structure having nanocrystals with average particle sizes of less than 40 nm dispersed in an amorphous matrix, the nanocrystals occupying more than 30 volume percent of the ribbon and has a radius of ribbon curvature of at least 200 mm.

A method for producing a magnetic core includes a processing step of giving a desired shape to a strip made of an alloy composition, a heat-treating step of forming bcc-Fe crystals, and then a stacking step of obtaining a magnetic core having a shape. Here, the alloy composition is Fe—B—Si—P—Cu—C and has an amorphous phase as a primary phase. In the heat-treating step, the strip is heated up to a temperature higher than a crystallization temperature of the alloy composition at a high heating rate.

A method for producing a magnetic core includes a processing step of giving a desired shape to a strip made of an alloy composition, a heat-treating step of forming bcc-Fe crystals, and then a stacking step of obtaining a magnetic core having a shape. Here, the alloy composition is Fe—B—Si—P—Cu—C and has an amorphous phase as a primary phase. In the heat-treating step, the strip is heated up to a temperature higher than a crystallization temperature of the alloy composition at a high heating rate.