Multivalent ionic conductivity in the series of phosphates LaxYb1/3 − xZr2(PO4)3 with NASICON structure

The electric conductivity at elevated temperatures has been measured for the series of orthophosphates LaxYb1/3 − xZr2(PO4)3, where x = 0, 1/18, 1/9, 1/6, 2/9, 5/18, and 1/3. They belong to the family of NASICON compounds, which are known to possess trivalent ionic conductivity. The method of infrared spectroscopy has been applied to determine structural transition P3̄ → P3̄c. These data correlate well with the observed conductivity values plotted against composition.

Research Highlights
► Phosphates LaxYb1/3-xZr2(PO4)3 were synthesized by the precipitation method.
► The compounds were characterized by XRD, IR spectroscopy, AFM and SEM techniques.
► Phase transition P3–→ P3–c within the series was determined.
► Ionic conductivity was measured by the method of complex impedance.
► The obtained conductivity data correlate well with the observed phase transition.