0000000000614064
AUTHOR
Marcel Salamon
Self-diffusion of silicon in molybdenum disilicide
The self-diffusion of silicon in single crystal MoSi2 was studied by means of a radiotracer technique using the short-lived radioisotope 31Si (half-life ), which was produced and implanted into the samples at the ion-guide isotope separator on-line device at the University of Jyvaskyla in Finland. Diffusion annealing and subsequent serial sectioning of the specimens were performed immediately after the radiotracer implantation. In the entire temperature region investigated (835–1124 K), the 31Si diffusivities in both principal directions of the tetragonal MoSi2 crystals obey Arrhenius laws, where the diffusion perpendicular to the tetragonal axis is faster than parallel to it. In previous s…
Si self-diffusion in cubic B20-structured FeSi
Self-diffusion of implanted 31Si in the e-phase FeSi (cubic B20-structure) has been determined in the temperature range 660–810 °C using the modified radiotracer technique. With an activation enthalpy of 2.30 eV and a pre-exponential factor of 15×10−8 m2 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 71Ge radioisotopes may be used to substitute the short-lived 31Si radiotracers when estimating self-diffusion in silicides.