Activation volume for nanocrystal growth in amorphous Nd_(9)Fe_(85)B_(6)

摘要

We have measured the pressure dependence of the growth of alpha-Fe and Nd_(2)Fe_(14)B nanocrystals in amorphous Nd_(9)Fe_(85)B_(6) up to 6 GPa at a temperature of 923 K, yielding an activation volume of (DELTA)V~(*)velence(0.76 +- 0.04) and (0.57 +- 0.05)OMEGA for atomic diffusion in the growth process of alpha-Fe and Nd_(2)Fe_(14)B nanocrystals, respectively, where OMEGA is the mean atomic volume of the alloy. This demonstrates that the growth of nanocrystals is dependent on atomic diffusion mediated by vacancy-type thermal defects. Atomic processes of the growth of nanocrystals are discussed.