Universality of Conductance Peak in Ferroeletric Phase Transition: Impurity Doped BaTiO₃ and (Pb(Zn_1/3Nb_2/3)O₃)_0.92(PbTiO₃)_0.08 Single Crystals

Abstract

The temperature (T) dependence of the quasi-equilibrium conductivity (T) of iron-doped, oxygen-reduced, and undoped BaTiO ₃ single crystals and relaxor (Pb(Zn _{1 /3} Nb _2/3 )O ₃ ) _0.92 (PbTiO ₃ ) _0.08 (PZNT-PT) crystals is measured. We have found that all the σ-T's exhibit the peaking at Curie temperature as far as the conductance in the paraelectric phase is sufficiently low. The value of the σ peaks of BaTiO ₃ single crystals is approx. 1 nΩ^{− 1}cm^{− 1} and is independent of impurities, whereas σ of the paraelectric phase depends on impurities. We speculate that the conductance peaking at phase transitions is a general property of ferroelectrics.

Keywords:

• conduction
• phase transition
• polarization

Acknowlegments

This work is supported by Grants-in-aid for Scientific Research from JSPS No. 16340093 and No. 17651063.