Effect of electromechanical boundary conditions on the properties of epitaxial ferroelectric thin films |
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| Authors: | Zhou Zhi-Dong Zhang Chun-Zu and Jiang Quan |
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| Institution: | Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005, China; Department of Civil Engineering, School of Architecture and Civil Engineering, Xiamen University, Xiamen 361005, China; College of Civil Engineering, Nantong University, Nantong 226019, China |
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| Abstract: | The effects of internal stresses and depolarization fields on the properties of epitaxial ferroelectric perovskite thin films are discussed by employing the dynamic Ginzburg-Landau equation (DGLE). The numerical solution for BaTiO3 film shows that internal stress and the depolarization field have the most effects on ferroelectric properties such as polarization, Curie temperature and susceptibility. With the increase of the thickness of the film, the polarization of epitaxial ferroelectric thin film is enhanced rapidly under high internal compressively stress. With the thickness exceeding the critical thickness for dislocation formation, the polarization increases slowly and even weakens due to relaxed internal stresses and a weak electrical boundary condition. This indicates that the effects of mechanical and electrical boundary conditions both diminish for ferroelectric thick films. Consequently, our thermodynamic method is a full scale model that can predict the properties of ferroelectric perovskite films in a wide range of film thickness. |
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| Keywords: | ferroelectric film internal stresses thermodynamic equations polarizations |
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