Ferroelectric, dielectric and leakage current properties of epitaxial (K,Na)NbO3-LiTaO3-CaZrO3 thin films
Ferroelectric, dielectric and leakage current properties of epitaxial (K,Na)NbO3-LiTaO3-CaZrO3 thin films
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DOI：
10.1007/s10832-014-9981-6
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发表时间：
2015-01
影响因子：
1.7
通讯作者：
Yuan-Hang Li;Feng Chen;Guan-Yin GAO;Haoran Xu;Wenbin Wu
中科院分区：
文献类型：
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作者：
Yuan-Hang Li;Feng Chen;Guan-Yin GAO;Haoran Xu;Wenbin Wu
采用La0.7Sr0.3MnO3作为底电极，在不同的氧压（15-45 Pa）和衬底温度（600-720 °C）下，在SrTiO 3（001）衬底上沉积了外延0.95（Na0.49K0.49Li0.02）（Nb0.8Ta0.2）-0.05CaZrO 3薄膜。利用高分辨率X射线衍射（XRD）、极化电滞（P-E）和漏电流（I-V）等测试手段，对样品的微观结构、铁电和介电性能进行了研究。结果表明，薄膜的晶格常数随沉积温度的升高而增大，而在氧分压变化时，薄膜的晶格常数几乎保持不变。薄膜的结晶度随着氧分压的增加而增加。得到了所有薄膜的饱和P-E环。在680 °C和35 Pa下制备的薄膜在1 kHz下的介电常数为1185，剩余极化（2 Pr）为28.0 μC/cm 2，矫顽场（2 Ec）为165.4 kV/cm。随着外加电场的增加，薄膜中的输运机制依次为空间电荷限制电流和Pool-Frenkel模型。
Epitaxial 0.95(Na0.49K0.49Li0.02) (Nb0.8Ta0.2)-0.05CaZrO3thin films were deposited under various oxygen pressures (15–45 Pa) and substrate temperatures (600–720 °C) on SrTiO3(001) substrates using La0.7Sr0.3MnO3as bottom electrodes. Their microstructures, ferroelectric and dielectric properties were intensively investigated with high-resolution X-ray diffraction (XRD), polarization- electric field hysteresis (P-E) measurements and leakage currents (I-V) characterizations. It is found that the lattice constant of the films increases with increasing deposition temperature, while it nearly keeps a constant even when the oxygen pressures are changed. The crystallinity of the films shows an increment with increasing oxygen partial pressure. SaturatedP-Eloops are obtained for all the films. The film fabricated with optimized parameters at 680 °C and 35 Pa displays a dielectric constant of 1185 at 1 kHz, a remnant polarization (2Pr) of 28.0 μC/cm2and a coercive field (2Ec) of 165.4 kV/cm.I-Vresults revealed that the ohmic conduction, space charge limited current and Pool-Frenkel model came up as predominant transport mechanism in the films in turn with the increment of applied electric field.