REDUCED-TEMPERATURE CRYSTALLIZATION OF THIN AMORPHOUS FE80B20 FILMS STUDIED VIA EMPIRICAL MODELING OF EXTENDED X-RAY-ABSORPTION FINE-STRUCTURE

The evolution of the local atomic environment around Fe atoms in very thin (15 nm), amorphous, partially crystallized and fully crystallized films of Fe80B20 was studied using extended x-ray absorption fine str ucture (EXAFS) measurements. The relative atomic fraction of each crys talline phase present in the annealed samples was extracted from the F e EXAFS data by a least-squares fitting procedure, using data collecte d from t-Fe3B, t-Fe2B, and alpha-Fe standards. The type and relative f raction of the crystallization products follows the trends previously measured in Fe80B20 melt-spun ribbons, except for the fact that crysta llization temperatures are approximate to 200 K lower than those measu red in bulk equivalents. This greatly reduced crystallization temperat ure may arise from the dominant role of surface nucleation sites in th e crystallization of very thin amorphous films. (C) 1996 American Inst itute of Physics.