[17a-411-1~11] 6.1 Ferroelectric thin films

[17a-411-1] Temperature dependence of lattice constants in epitaxial BaTiO₃ thin films with in-plane ferroelectric polarization

〇(PC)Katsuyoshi Komatsu¹, Ippei Suzuki¹, Takumi Aoki², Yosuke Hamasaki¹, Shintaro Yasui¹, Mitsuru Itoh¹, Taniyama Tomoyasu¹ (1.Titech, 2.TDK)

Keywords:ferroelectric thin film

In-plane ferroelectricity allows electrical control of in-plane strain. Therefore, the electric states or magnetic properties of the materials which are deposited on the in-plane ferroelctric material can be controlled by electric field. In this study, we achieved in-plane polarization in BaTiO₃ epitaxial thin films on spinel MgAl₂O₄ substrates. Angle dependence of polarization and Raman spectroscopy shows that the crystal structure is orthorhombic. Furthermore, Curie temperature is enhanced to 220 ℃ compared with 120 ℃ of bulk BTO. These are important results towards the application to electrical strain-control devices.