Si Self-Diffusion In Cubic B20-Structured Fesi

Self-diffusion of implanted Si-31 in the epsilon-phase FeSi (cubic B20-structure) has been determined in the temperature range 660-810 degrees C using the modified radiotracer technique. With an activation enthalpy of 2.30 eV and a pre-exponential factor of 15 x 10(-8) m(2) s(-1) the silicon diffusivity was found to be slightly slower than Ge impurity diffusion in FeSi. This difference is proposed to originate from attractive elastic interactions prevailing between the slightly oversized Ge atoms and the Si sublattice vacancies. The results confirm the argument that Ge-71 radioisotopes may be used to substitute the short-lived Si-31 radiotracers when estimating self-diffusion in silicides. Copyright (C) EPLA, 2008.