Influence of antiferromagnetic ordering on ferroelectric polarization switching of YMnO/sub 3/ epitaxial thin films

In this study, the switching behavior of ferroelectric polarization of (0001) YMnO₃ epitaxial films at around Neel temperature was investigated. From the experimental results of the frequency and temperature dependences of coercive electric filed (Ec) obtained from polarization-electric field (P-E) hysteresis loop, the cross-correlation phenomena between magnetics and ferro-electrics are discussed in detail. The P-E hysteresis loops of the films were measured in the frequency range from 1 Hz to 10 kHz, and the temperature was varied from 10 to 150 K. Frequency dependence of Ec accorded with Ishibashi-Orihara´s theory at the measured temperature range. However, temperature dependence of Ec disagreed with Devonshire´s theory below 120 K, which is close to the Neel temperature of the YMnO₃ epitaxial film.