Electric conductivity and lattice disorder of PbMoO 4 crystals

From differential thermal analysis (DTA), thermal etching, perfectly reversable redox treatments and electric conductivity it is concluded that the Pb/Mo ratio of the PbMoO 4 crystals is always 1 and that phase transitions do not occur. Pb 3+ ions detectable by an absorption band at 435 nm cause a p‐conductivity due to the reaction Pb 3+ ⇌ Pb ++ + e + . At elevated temperatures the p‐conductivity increases with increasing oxygen partial pressure of the surrounding atmosphere. The influence of foreign ions on the concentration of ionic and electronic defects in PbMoO 4 , CaMoO 4 , PbO, and PbTiO 3 can be explained by an anti‐Frenkel disorder of the oxygen ion sublattice. For PbMoO 4 crystals the mobility O − ion vacancies and the free formation enthalpy of anti‐Frenkel defects are found to be v v = \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop - \limits_T^{9160} $\end{document} exp (−1.15 eV/ kT ) cm 2 K/Vs and g AF = 3.6 kT −2.2 eV, respectively.