A soft magnetic powder containing a particle having a composition represented by Fe.sub.xCu.sub.aNb.sub.b(Si.sub.1-yB.sub.y).sub.100-x-a-b, a, b, and x being numbers whose units are atomic %, in which 0.3≤a≤2.0, 2.0≤b≤4.0, 75.5≤x≤79.5, and y is a number satisfying f(x)≤y≤0.99, and f(x)=(4×10.sup.−34)x.sup.17.56. The particle includes a crystal grain having a grain size of 1.0 nm or more and 30.0 nm or less and containing a Fe—Si crystal, a Cu segregation portion having a grain size of 2.0 nm or more and 16.0 nm or less in which Cu is segregated, and a crystal grain boundary adjacent to the crystal grain and having a Nb concentration and a B concentration higher than a Nb concentration and a B concentration in the crystal grain. A number proportion of the Cu segregation portion is 80% or more.

A crystalline Fe-based alloy powder composed of Fe-based alloy particles containing, within a structure thereof, nanocrystal grains having an average grain size of 30 nm or less, and in which d50, which is a particle diameter corresponding to a cumulative frequency of 50% by volume, is from 3.5 μm to 35.0 μm in a cumulative distribution curve that is obtained by laser diffractometry and that shows the relationship between the particle diameter and the cumulative frequency from the small particle diameter side, and a ratio of Fe-based alloy particles having a particle diameter of 2 μm or less to the total of the Fe-based alloy particles, which is determined by laser diffractometry, is from 0% by volume to 8% by volume.

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 1.25 T. 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 soft magnetic alloy includes a composition of (Fe.sub.(1-(α+β))X1.sub.αX2.sub.β).sub.(1-(a+b+c+d+e+f+g))M.sub.aTi.sub.bB.sub.cP.sub.dSi.sub.eS.sub.fC.sub.g. X1 is one or more of Co and Ni. X2 is one or more of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, O, and rare earth elements. M is one or more of Nb, Hf, Zr, Ta, Mo, W, and V. 0.020≤a+b≤0.140, 0.001≤b≤0.140, 0.020<c≤0.200, 0.010≤d≤0.150, 0≤e≤0.060, a≥0, f≥0, g≥0, a+b+c+d+e+f+g<1, α≥0, β≥0, and 0≤α+β≤0.50 are satisfied. The soft magnetic alloy has a nanohetero structure or a structure of Fe-based nanocrystalline.

A soft magnetic alloy and the like which simultaneously satisfy a high saturation magnetic flux density Bs and a high corrosion resistance. A soft magnetic alloy includes Mn and a component expressed by a compositional formula of ((Fe.sub.(1−(α+β))Co.sub.αNi.sub.β).sub.1−γX1.sub.γ).sub.(1−(a+b+c+d+e))B.sub.aP.sub.bSi.sub.cC.sub.dCr.sub.e (atomic ratio). X1 is one or more selected from Ti, Zr, Hf, Nb, Ta, Mo, W, Al, Ga, Ag, Zn, S, Ca, Mg, V, Sn, As, Sb, Bi, N, O, Au, Cu, rare earth elements, and platinum group elements. Further, a to e and α to γ are within predetermined ranges. Mn amount f (at %) is within a range of 0.002≤f<3.0. The soft magnetic alloy satisfies a corrosion potential of −630 mV or more and −50 mV or less and a corrosion current density of 0.3 μA/cm.sup.2 or more and 45 μA/cm.sup.2 or less.

A soft magnetic alloy or the like combining high saturated magnetic flux density, low coercive force and high magnetic permeability μ′ having the composition formula (Fe.sub.(1−(α+β))X1.sub.αX2.sub.β).sub.(1−(a+b+c+d+e))B.sub.aSi.sub.bC.sub.cCu.sub.dM.sub.e. X1 is one more elements selected from the group consisting of Co and Ni, X2 is one or more elements selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Bi, N, O and rare earth elements, and M is one or more elements selected from the group consisting of Nb, Hf, Zr, Ta, Ti, Mo, W and V. 0.140<a≤0.240, 0≤b≤0.030, 0<c<0.080, 0<d≤0.020, 0≤e≤0.030, α≥0, β≥0, and 0≤α+β≤0.50 are satisfied.

A soft magnetic core of an inductor or a motor core includes an alloy having a composition of Fe, Si, B, P, Cu, and Y, and the soft magnetic core or the motor core has a composite structure in which crystal grains including Fe are dispersed in an amorphous phase. Also, the alloy is expressed by the compositional formula Fe.sub.aSi.sub.bB.sub.cP.sub.dCu.sub.eY.sub.fC.sub.g, wherein a to g satisfy 80≤a≤87, 0≤b≤9, 3≤c≤14, 1≤d≤8, 0.2≤e≤2.5, 0≤f≤3.0, 0≤g≤4.0, and 0≤(e/f)≤4 in terms of atomic percentage value.

An Fe-based amorphous alloy ribbon reduced in iron loss, less deformed, and highly productive in a condition of a magnetic flux density of 1.45 T is provided. One aspect of the present disclosure provides an Fe-based amorphous alloy ribbon having first and second surfaces, and is provided with continuous linear laser irradiation marks on at least the first surface. Each linear laser irradiation mark is formed along a direction orthogonal to a casting direction of the Fe-based amorphous alloy ribbon, and has unevenness on its surface. When the unevenness is evaluated in the casting direction, a height difference HL×width WA calculated from the height difference HL between a highest point and a lowest point in a thickness direction of the Fe-based amorphous alloy ribbon and the width WA which is a length of the linear irradiation mark on the first surface is 6.0 to 180 μm.sup.2.

Provided is soft magnetic powder containing an amorphous metal particle having a composition expressed by a compositional formula Fe.sub.100-a-b-c-d-e-f-gCr.sub.aSi.sub.bB.sub.cC.sub.dAl.sub.eTi.sub.fCo.sub.g. Here, a, b, c, d, e, f, and g are that express atom %, 0<a≤3.0, 5.0≤b≤15.0, 7.0≤c≤15.0, 0.1≤d≤3.0, 0<e≤0.016, 0<f≤0.009, and 0≤g≤0.025.

To obtain a magnetic core having an improved withstand voltage property while maintaining a high relative magnetic permeability, and the like. The magnetic core contains large particles observed as soft magnetic particles having a Heywood diameter of 5 μm or more and 25 μm or less and small particles observed as soft magnetic particles having a Heywood diameter of 0.5 μm or more and less than 5 μm in a cross section. C1<C2 is satisfied in which an average circularity of the small particles close to the large particles is C1 and an average circularity of all small particles observed in the cross section including small particles not close to the large particles is C2. The small particles close to the large particles are defined as small particles whose distance from centroids of the small particles to a surface of the large particles is 3 μm or less.