FORMATION OF AN AMORPHOUS PHASE IN CR-1-XFEX FILMS OBTAINED BY THERMAL EVAPORATION

Cr1-xFex alloy films (congruent to 3000 Angstrom) were prepared by the rmal coevaporation at room temperature at a deposition rate of 25 Angs trom/min. It was found that a pure amorphous phase can be obtained in the composition range 0.25 < x < 0.60, while out of this range the bcc crystalline phase appears. The structural characterization and the ma gnetic properties were studied by x-ray diffraction and Mossbauer spec troscopy, respectively. The crystallization temperature for an amorpho us Cr70Fe30 film was found to be about 630 K as determined by in situ Mossbauer measurements. Since Cr-Fe is not a ready-glass-forming syste m, the amorphization process was discussed through the thermodynamics of the system and the kinetics of the condensation process.