Superionic PbSnF4: A giant dielectric constant material

In this letter, the authors report on the giant dielectric constant properties in a hitherto unexplored material, the superionic conductor lead tin fluoride PbSnF4. Despite its superionic behavior, PbSnF4 is surprisingly found to exhibit extraordinary high dielectric constant (ε′∼105). ε′ is almost independent of temperature and frequency over wide ranges. The authors find that the high value of ε′ originates from an internal effect, such as internal barrier layer capacitor, rather than from a surface barrier layer capacitor formed at the electrode/sample interface.