Measurements of the pressure and temperature dependences of the ionic conductivity of CsCl combined with earlier diffusion and/or ionic conductivity measurements at atmospheric pressure have allowed determination of energies and volume relaxations associated with the formation and motion of Schottky defects in this crystal. An important result is that the lattice relaxation associated with vacancy formation is large and outward, the formation volume for Schottky pairs being 1.8-2.0 times the molar volume. The association energy of ${\mathrm{Cs}}^{+}$ vacancies and divalent cation impurities is estimated to be 0.36 eV.

• Received 31 July 1980

DOI:https://doi.org/10.1103/PhysRevB.22.6476