Enhanced remanence in flash-annealed Nd/sub 4/Fe/sub 78/B/sub 18/

Nanocrystalline Nd/sub 4/Fe/sub 78/B/sub 18/ was produced by affixing current leads directly to amorphous ribbons for flash-annealing. Ribbons were annealed in the range T/sub a/=650-1000/spl deg/C, for times 10-600 s. Flash-annealed ribbons show higher remanence ratios (M/sub r//M/sub s/=0.83) than those submitted to conventional furnace (680/spl deg/C/10 min) annealing (M/sub r//M/sub s/=0.74). In flash-annealed ribbons, Mossbauer spectroscopy and X-ray diffraction indicated the presence of the Nd/sub 2/Fe/sub 23/B/sub 3/ phase, in addition to Fe/sub 3/B, Nd/sub 2/Fe/sub 14/B, and /spl alpha/-Fe. Flash-annealing for short times at high temperatures may give H/sub c/ values up to 20% higher than furnace annealing. The isothermal remanent magnetization and the dc demagnetization remanence were found to be in reasonable agreement with the Wohlfarth relation.