A method is provided for the production of a wound nanocrystalline magnetic core in which a nanocrystalline metal strip made of (Fe.sub.1-aM.sub.a).sub.100-x-y-z--Cu.sub.xSi.sub.yB.sub.zM.sub.X.sub. is pre-wound to form a first coil. An insulating foil is provided that is coated with an adhesive on at least one side. An adhesive is applied to the nanocrystalline metal strip to laminate the insulating foil onto the metal strip and thereby to stabilise the metal strip as it is wound off the coil. The laminated nanocrystalline metal strip and the insulating foil are bifilar wound to form a bifilar, layer-insulated coil.

An inductor includes a first magnetic body having a toroidal shape and having a ferrite; and a second magnetic body configured to be different from the first magnetic body and including a metal ribbon, wherein the second magnetic body includes an outer magnetic body disposed on an outer circumferential surface of the first magnetic body and an inner magnetic body disposed on an inner circumferential surface of the first magnetic body, and each of the outer magnetic body and inner magnetic body is wound in a plurality of layers in a circumferential direction of the first magnetic body.

An inductor includes a first magnetic body having a toroidal shape and having a ferrite; and a second magnetic body configured to be different from the first magnetic body and including a metal ribbon, wherein the second magnetic body includes an outer magnetic body disposed on an outer circumferential surface of the first magnetic body and an inner magnetic body disposed on an inner circumferential surface of the first magnetic body, and each of the outer magnetic body and inner magnetic body is wound in a plurality of layers in a circumferential direction of the first magnetic body.

An amorphous metal ribbon includes a plurality of laser irradiation mark rows each including a plurality of laser irradiation marks arranged in a row, in which when a distance between the laser irradiation mark rows that are adjacent to each other is set as d1, a distance between the laser irradiation marks in the laser irradiation mark row is set as d2, a diameter of the laser irradiation mark is set as d3, and a number density D of the laser irradiation marks is set as (1/d1)?(1/d2), the number density D of the laser irradiation marks is 0.05 pieces/mm.sup.2 or more and 0.50 pieces/mm.sup.2 or less, and when an area occupancy rate A of the laser irradiation marks is set as D?(d3/2).sup.2???100, the area occupancy rate A of the laser irradiation marks is 0.0035% or more and 0.040% or less.

An amorphous metal ribbon includes a plurality of laser irradiation mark rows each including a plurality of laser irradiation marks arranged in a row, in which when a distance between the laser irradiation mark rows that are adjacent to each other is set as d1, a distance between the laser irradiation marks in the laser irradiation mark row is set as d2, a diameter of the laser irradiation mark is set as d3, and a number density D of the laser irradiation marks is set as (1/d1)?(1/d2), the number density D of the laser irradiation marks is 0.05 pieces/mm.sup.2 or more and 0.50 pieces/mm.sup.2 or less, and when an area occupancy rate A of the laser irradiation marks is set as D?(d3/2).sup.2???100, the area occupancy rate A of the laser irradiation marks is 0.0035% or more and 0.040% or less.

An inductor includes a first magnetic body having a toroidal shape and having a ferrite; and a second magnetic body configured to be different from the first magnetic body and including a metal ribbon, wherein the second magnetic body includes an outer magnetic body disposed on an outer circumferential surface of the first magnetic body and an inner magnetic body disposed on an inner circumferential surface of the first magnetic body, and each of the outer magnetic body and inner magnetic body is wound in a plurality of layers in a circumferential direction of the first magnetic body.

An inductor includes a first magnetic body having a toroidal shape and having a ferrite; and a second magnetic body configured to be different from the first magnetic body and including a metal ribbon, wherein the second magnetic body includes an outer magnetic body disposed on an outer circumferential surface of the first magnetic body and an inner magnetic body disposed on an inner circumferential surface of the first magnetic body, and each of the outer magnetic body and inner magnetic body is wound in a plurality of layers in a circumferential direction of the first magnetic body.

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 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 ?m.sup.2.

A specific depth at which a concentration of Fe reaches 10 at % is 18 nm or more and 500 nm or less from the first surface, and from the first surface to the specific depth, the concentration of Fe is less than 10 at %, and a positive increase region is present in which the concentration of Fe increases with a substantially positive concentration gradient, in a case where the concentration of Fe is measured in a depth direction from a first surface of a ribbon.

A specific depth at which a concentration of Fe reaches 10 at % is 18 nm or more and 500 nm or less from the first surface, and from the first surface to the specific depth, the concentration of Fe is less than 10 at %, and a positive increase region is present in which the concentration of Fe increases with a substantially positive concentration gradient, in a case where the concentration of Fe is measured in a depth direction from a first surface of a ribbon.