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.

I. Introduction

Multiferroic materials, which exhibit two or more ferroic features such as ferroelectric, have recently attracted much attention because of their potential use in spintronics devices. In these materials, the magnetization could be switched by applying an electric field, and the ferroelectric polarization could be switched by applying a magnetic field due to the possible coupling between the magnetic and electronic structures [1]–[6].