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A b s t r a c t -N a n o c r y s t a l l i n e N d q F e 7 g B 1 8 w a s produced by affixing current leads directly to amorphous ribbons for flash-annealing. Ribbons were annealed in the range Ta = 650-10OO0C, for times 10-600 s. Flash-annealed ribbons show higher remanence ratios (Mr/Ms 0.83) than those submitted to conventional furnace (68O0C/1O min) annealing ( M r / M e 0.74). In flash-annealed ribbons, Mossbauer spectroscopy and xr a y d i f f~a c~~o n indicated the presence of the Nd2Fe23B3 phase, in addition to Fe3B, NdzFelqB, and a -F e . F l a s h -a n n e a l i n g for short times at high temperatures may give Hc values up to 20% higher than furnace annealing. The isothermal r e m a n e n t magnetization and the dc d e m a g n e t i z a t i o n remanence were found to be in reasonable agreement with the Wohlfarth relation.

SummaryThis paper reports on the development of a magneto-optical scanning near-field optical microscope and the experimental near-field study of the domain structure for a model magnetic particle of 16 × 16 µ m 2 of a Co 70.4 Fe 4.6 Si 15 B 10 amorphous thin film, deposited on a silicon substrate. We present the topographic, optical and magneto-optical differential susceptibility (MODS) images of the particle. Imaging by using the local MODS reveals the domain structure. These images are also used for positioning the tip in order to acquire local hysteresis loops, with submicrometre spatial resolution.

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