Mixed conduction in BaF2 nanocrystals under high pressure
The charge transport behavior of barium fluoride nanocrystals has been investigated by in situ impedance measurement up to 23 GPa. It was found that the parameters changed discontinuously at each phase transition. The charge carriers in BaF2 nanocrystals include both F− ions and electrons. Pressure makes both the F− ions diffusion and electronic transport more difficult. The defects at grains dominate the electronic transport process. Pressure could make the charge–discharge processes in the Fm3m and Pnma phases more difficult. The electron conduction plays a dominant role in the transport process. In the Fm3m and Pnma phases, the electron transference number increases with increasing pressure.