Ion mobility in a sodium-doped PbMoO4 crystal

The temperature and frequency dependences of the absorption coefficient of longitudinal acoustic waves, traveling parallel to the z and x axes of nominally pure and sodium-doped PbMoO 4 crystals, revealed a high mobility of sodium ions, which was of quasione-dimensional nature along the z axis. Estimates were obtained of the activation enthalpies and of the attempt frequencies of different relaxation processes due to the hopping motion of sodium