Soft magnetic alloy ribbon and magnetic core

A soft magnetic alloy ribbon made of a Fe-based soft magnetic alloy, the soft magnetic alloy ribbon comprising:

• a first laser peening trace row and a second laser peening trace row each of which includes a plurality of laser peening traces in a row in a first direction and which are arranged adjacent to each other in a second direction intersecting the first direction;
• and
• a domain wall extending in a third direction intersecting the first direction, wherein
• D0<D1
• where a straight line at an equal separation distance from the first laser peening trace row and the second laser peening trace row is defined as a central line,
• a straight line which is located on a central line side of the first laser peening trace row and has a first distance where a distance from the first laser peening trace row is shorter than the separation distance is defined as a first reference line,
• a width of the domain wall at a position intersecting the central line is defined as D0,
• a width of the domain wall at a position intersecting the first reference line is defined as D1,
• a width of the soft magnetic alloy ribbon is 5 mm or more and 500 mm or less,
• a thickness of the soft magnetic alloy ribbon is 1 μm or more and 40 μm or less,
• the Fe-based soft magnetic alloy is an Fe—SI—B alloy or an Fe—Si—B—C alloy,
• the Fe-based soft magnetic alloy contains at least one of an amorphous structure and a nanocrystalline structure in a total of 50 volume % or more,
• the spot spacing between the laser peening traces is 1.0 mm or less,
• the spot diameter of the laser peening traces is 0.010 mm or more and 0.30 mm or less, and
• the spot depth of the laser peening traces is 0.0020 mm or more and 0.15 mm or less.