Europium Diffusion in SmS

Abstract

Europium diffusion in samarium sulfide was studied in the temperature range from 780 to 1100°C. Data on the diffusion coefficient and activation energies for the diffusion of europium in single-crystal and polycrystalline SmS samples were obtained. In single-crystal samarium sulfide, europium was shown to migrate predominantly over lattice sites (D ≃ 10−12−10−9 cm2/s). In SmS polycrystals, diffusion was found to exhibit a complex pattern and have both a slow (D ≃ 10−10−10−9 cm2/s) and a fast (D ≃ 10−8−10−7 cm2/s) component. Europium diffusion in a polycrystal is primarily due to europium migration over the boundaries of single-crystal grains in the polycrystal, whose characteristic size is assumed to be that of x-ray coherent-scattering regions.