Electrical Properties of Tungstates Ln2(WO4)3 (Ln – Gd, Ho)

<p>Electrical properties of Gd₂(WO₄)₃ and Ho₂(WO₄)₃ were studied and the type of charge carriers was determined. The studied compounds have a salt-like isle structure with isolated tetrahedrons. It crystallises in the Еu₂(WO₄)₃ structural type, so-called ‘defective scheelite’, in which 1/3 of Ln sites are vacant, Ln_2/3[V_Ln]_1/3WO₄. Predominant ionic conductivity in Ln₂(WO₄)₃ (Ln = Gd, Ho) was established both by the EMF method and from independence of conductivity versus oxygen partial pressure. A minor contribution (4-11%) of the anion [WO₄]^2- transport was detected by the Tubandt method, which along with the results of the EMF technique proves the predominant oxygen conductivity.</p>