Electrical conductivity of CsCuCl3 crystals at structural phase transition

Resumo

The electrical conductivity σ of CsCuCl₃ single crystals synthesized by the crystallization method from aqueous solutions in the ternary CsCl–CuCl₂–H₂O system has been studied. The σ measurements for CsCuCl₃ crystals have been carried out in the temperature range of 397–455 K, which covers the structural phase transition from the low-temperature (sp. gr. P6₁22, Z = 6) to the high-temperature (sp. gr. P6₃mc, Z = 2) modification at T_tr = 423 ± 8 K. A jump of σ by a factor of ~3 is observed on the σ(T) dependence in the region of the structural transition, which indicates the existence of first-order phase transition. The electric transfer activation enthalpies ΔHσ are found to be 1.0 ± 0.1 eV at T > T_tr and 0.8 ± 0.1 eV at T < T_tr. The σ value for CsCuC_l3 crystals amounts to 7 × 10^–6 S/cm at 455 K.