Fig. 7: P-T curves and corresponding domain structures of PTO.

a P-T curves of PTO bulk domains and nanodomains under temperature 300 ~ 700 °C, b bulk domain structure at initial state, c nanodomain at initial state, d bulk domain at A point e nanodomain at B point under 100 kV/cm and 400 °C. (Local magnified polarizations are in the red lines).