abstract a ferromagnetic amorphous alloy ribbon includes an alloy having a composition represented by fe a si b b c c d where 80 5 u2266 a u2266 83 at 0 5 u2266 b u2266 6 at 12 u2266 c u2266 16 5 at 0 01 u2266 d u2266 1 at with a b c d 100 and incidental impurities the defect length along a direction of the ribbon 39 s length being between 5 mm and 200 mm the defect depth being less than 0 4 u00d7 t u03bcm and the defect occurrence frequency being less than 0 05 u00d7 w times within 1 5 m of ribbon length where t and w are ribbon thickness and ribbon width respectively and the ribbon in its annealed state and straight strip form of the ribbon has a saturation magnetic induction exceeding 1 60 t and exhibits a magnetic core loss of less than 0 14 w kg when measured at 60 hz and at 1 3 t induction level the ribbon is suitable for use in transformer cores rotational machines electrical chokes magnetic sensors and pulse power devices application_number US 92307410 A description an amorphous alloy ribbon can be prepared as taught in u s pat no 4 142 571 by having a molten alloy ejected through a slotted nozzle onto a rotating chill body surface the ribbon surface facing the chill body surface looks dull but the opposite side surface facing atmosphere is.