| abstract |
An ultrafine-crystalline alloy ribbon having a composition represented by the general formula of Fe100-x-y-zAxByXz, wherein A is Cu and/or Au, X is at least one element selected from the group consisting of Si, S, C, P, Al, Ge, Ga and Be, and x, y and z are numbers meeting the conditions of 0<x≤5, 8≤y≤22, 0≤z≤10, and x+y+z≤25 by atomic %, and a structure in which ultrafine crystal grains having an average particle size of 30 nm or less being dispersed in a proportion of more than 0% and less than 30% by volume in an amorphous matrix; an ultrafine crystal grains-depleted region comprising ultrafine crystal grains at a number density of less than 500/μm2 being formed in a region of 0.2 mm in width from each side of the ribbon. |