Piezoelectric and Dielectric Properties of Multilayered BaTiO3/(Ba,Ca)TiO3/CaTiO3 Thin Films

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• 作者：Xiao Na Zhu ; Ting Ting Gao ; Xing Xu ; Wei Zheng Liang ; Yuan Lin ; Chonglin Chen ; Xiang Ming Chen
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：August 31, 2016
• 年：2016
• 卷：8
• 期：34
• 页码：22309-22315
• 全文大小：734K
• 年卷期：0
• ISSN：1944-8252

文摘

Highly oriented multilayered BaTiO₃–(Ba,Ca)TiO₃–CaTiO₃ thin films were fabricated on Nb-doped (001) SrTiO₃ (Nb:STO) substrates by pulsed laser deposition. The configurations of multilayered BaTiO₃–(Ba,Ca)TiO₃–CaTiO₃ thin films are designed with the thickness ratio of 1:1:1 and 2:1:1 and total thickness ∼300 nm. Microstructural characterization by X-ray diffraction indicates that the as-deposited thin films are highly c-axis oriented and large in-plane strain is determined in BaTiO₃ and CaTiO₃ layers. Piezoresponse force microscopy (PFM) studies reveal an intense in-plane polarization component, whereas the out-of-plane shows inferior phase contrast. The optimized combination is found to be the BaTiO₃–(Ba_0.85Ca_0.15)TiO₃–CaTiO₃ structure with combination ratio 2:1:1, which displays the largest domain switching amplitude under DC electric field, the largest room-temperature dielectric constant ∼646, a small dielectric loss of 0.03, and the largest dielectric tunability of ∼50% at 400 kV/cm. These results suggest that the enhanced dielectric and tunability performance are greatly associated with the large in-plane polarization component and domain switching.