Site preference of vanadium doped into ZrSiO4 and ZrGeO4 and of terbium doped into ZrGeO4

Abstract

The site which vanadium prefers to occupy in ZrSiO₄(zircon) and ZrGeO₄ and which terbium prefers occupy in ZrSiO₄ has been investigated by lattice-energy calculations, electron-probe analysis, and X-ray diffraction. Lattice-energy calculations on pure and doped ZrO₂ and ZrSiO₄ using CASCADE computer codes indicate that, although the energies required to substitute V⁴⁺ for Si⁴⁺ and Zr⁴⁺ in each host material are very similar to one another, more distortion of the lattice takes place on substitution for Si⁴⁺ than for Zr⁴⁺. Both electron-probe analysis and X-ray diffraction indicate that vanadium dopes into both the Zr⁴⁺ and the Si⁴⁺ sites of ZrSiO₄, into the Ge⁴⁺ site of ZrGeO₄, and that terbium dopes into the Zr⁴⁺ site of ZrGeO₄.