A magnetic core includes a nanocrystalline alloy ribbon having a composition represented by FeCu.sub.xB.sub.ySi.sub.zA.sub.aX.sub.b, where 0.6≤x<1.2, 10≤y≤20, 0≤(y+z)≤24, and 0≤a≤10, 0≤b≤5, all numbers being in atomic percent, with the balance being Fe and incidental impurities, and 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. The nanocrylstalline alloy ribbon has a local structure such that nanocrystals with average particle sizes of less than 40 nm are dispersed in an amorphous matrix and are occupying more than 30 volume percent of the ribbon.

A method for producing an Fe-based nanocrystalline alloy ribbon, the method including a step of supplying a molten Fe-based alloy onto a rotating chill roll, and rapidly solidifying the molten Fe-based alloy that has been supplied onto the chill roll, thereby obtaining an Fe-based amorphous alloy ribbon having a free solidified surface and a roll contact surface, and a step of heat-treating the Fe-based amorphous alloy ribbon, thereby obtaining an Fe-based nanocrystalline alloy ribbon; wherein an outer peripheral part of the chill roll is composed of a Cu alloy, and a thermal conductivity of the outer peripheral part is from 70 W/(m.Math.K) to 225 W/(m.Math.K).

An amorphous soft magnetic alloy of the formula (Fe.sub.1-αTM.sub.α).sub.100-w-x-y-zP.sub.wB.sub.xL.sub.ySi.sub.z Ti.sub.pC.sub.qMn.sub.rCu.sub.s, wherein TM is Co or Ni; L is Al, Cr, Zr, Mo or Nb; 0≦α≦0.3, 2≦w≦18 at %, 2≦x≦18 at %, 15≦w+x≦23 at %, 1<y≦5 at %, 0≦z≦4 at %; p, q, r, and s represents an addition ratio such that the total mass of Fe, TM, P, B, L and Si is 100, and 0≦p≦0.3, 0≦q≦0.5, 0≦r≦2, 0≦s≦1 and r+s>0; the composition fulfills one of the following conditions: L is Cr, Zr, Mo or Nb; or L is a combination of Al and Cr, Zr, Mo or Nb, wherein 0<Al≦5 at %, 1≦Cr≦4 at %, 0<Zr≦5 at %, 2≦Mo≦5 at %, and 2≦Nb≦5 at %; the alloy has a crystallization start temperature (Tx) which is 550° C. or less, a glass transition temperature (Tg) which is 520° C. or less, and a supercooled liquid region represented by ΔTx=Tx−Tg, which is 20° C. or more.

A method of manufacturing an amorphous alloy magnetic core, which includes preparing a layered body by layering amorphous alloy thin strips one on another, and has one end face and another end face in a width direction of the thin strips and an inner peripheral surface and an outer peripheral surface orthogonal to a layering direction of the thin strips; forming a hole passing through from the one end face of the layered body as a starting point; subjecting the layered body to which the hole has been formed to a heat treatment while measuring an internal temperature of the hole; and forming a resin layer which blocks the hole and covers at least a part of the one end face by coating and curing a two-liquid mixed type epoxy resin composition having a viscosity of from 38 Pa.Math.s to 51 Pa.Math.s and a T. I. value of from 1.6 to 2.7 on at least a part of at least the one end face of the layered body after being subjected to the heat treatment.

An amorphous alloy magnetic core including a layered body in which amorphous alloy thin strips are layered one on another, the layered body having one end face and another end face in a width direction of the amorphous alloy thin strips, an inner peripheral surface and an outer peripheral surface orthogonal to a layering direction of the amorphous alloy thin strips, and a hole passing through from a part of the one end face as a starting point, the width direction corresponding to a depth direction of the hole.

In a single phase transformer core and transformer, thin-strip metal is wound into multiple rings of different widths and arranged to define a ring-like structure having a stepped, substantially circular cross-section without any cuts or gaps in the magnetic path, or the core is wound from a tapered strip that is configured to define a substantially circular cross-section when wound, while in a three phase transformer core and transformer two inner frames, each made of one or more wound rings are arranged side-by-side and an outer frame of one or more rings is wound around the two inner frames, the core being covered with epoxy prior to winding coils on it.

An amorphous alloy magnetic core including a layered body in which amorphous alloy thin strips are layered one on another, the layered body having one end face and another end face in a width direction of the amorphous alloy thin strips, an inner peripheral surface and an outer peripheral surface orthogonal to a layering direction of the amorphous alloy thin strips, and a hole passing through from a part of the one end face as a starting point, the width direction corresponding to a depth direction of the hole.

There is provided a method for producing metal foils, capable of easily crystalizing amorphous soft magnetic material of a plurality of metal foils into nano-crystal magnetic by uniformly heating the metal foils. Separating members (magnets) are disposed on the opposite sides of a laminate, which has been obtained by laminating a plurality of metal foils made of amorphous soft magnetic material, in the laminated direction of the laminate, and the metal foils forming the laminate are magnetized with the magnets. Thus, the adjacent metal foils are separated from each other in the laminated direction and a gap is formed between the metal foils. The metal foils are heated with the gap formed therebetween so that the amorphous soft magnetic material of each metal foil is crystalized into nano-crystal magnetic material.

A heat treatment apparatus for a laminated body of amorphous alloy ribbon includes: a lamination jig that holds the laminated body of amorphous alloy ribbon; two heating plates that sandwich the laminated body from upper and lower surfaces in a lamination direction without coming into contact with the lamination jig; and a heating control apparatus that controls a heating temperature of the two heating plates.

An magnet embedded type motor capable of reducing a counter electromotive voltage while suppressing reduction of a torque is provided. The magnet embedded type motor of the present disclosure includes a stator and a rotor rotatably disposed inside the stator. The rotor includes a rotor core and a plurality of magnet groups embedded in the rotor core along a circumferential direction, the rotor core includes a plurality of laminated metal foils. The rotor core has a pair of radially arranged magnet holes, a center side magnetic flux leakage prevention hole, and center side bridge portions for each magnetic pole. A pair of radially arranged magnets are embedded in the radially arranged magnet holes. In the rotor core, the center side bridge portion, a center portion, and an inter-magnetic pole portion are made of a nanocrystalline soft magnetic material, and another portion is made of an amorphous soft magnetic material.