Effect of (Na,K)-Excess Precursor Solutions on Alkoxy-Derived (Na,K)NbO3 Powders and Thin Films
Effect of (Na,K)-Excess Precursor Solutions on Alkoxy-Derived (Na,K)NbO3 Powders and Thin Films
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DOI：
10.1143/jjap.46.6964
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发表时间：
2007-10
影响因子：
1.5
通讯作者：
Kiyotaka Tanaka;H. Hayashi;K. Kakimoto;H. Ohsato;T. Iijima
中科院分区：
文献类型：
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作者：
Kiyotaka Tanaka;H. Hayashi;K. Kakimoto;H. Ohsato;T. Iijima
采用溶胶-凝胶法，从化学计量比（Na/K=50/50）、4mol%过量（52/52、53/51和55/49）和10mol%过量（55/55、56/54、58/52和60/50）的前驱体溶液制备了无铅（Na 0.5K 0.5）NbO 3（NKN）粉末和薄膜。在800 °C下热处理的NKN 55/55粉末显示正交相和矩形晶粒，其尺寸估计为约300 nm。随着Na/K比的增加，晶粒尺寸增加到约1 μm，并且在差热分析（DTA）曲线中，在392 °C处出现α-四氢呋喃（Tc）相变峰。另一方面，在600 °C下从（Na，K）过量的前体溶液（58/52和60/50）制备单相NKN薄膜。特别是，NKN 58/52薄膜显示出低漏电流密度（40 kV/cm时为10-7 A/cm 2），1 kHz时的最大极化Pmax和介电常数εr分别为9.1 µC/cm 2和725。
Lead-free (Na0.5K0.5)NbO3 (NKN) powders and thin films were fabricated from stoichiometric (Na/K=50/50), 4 mol % excess (52/52, 53/51, and 55/49), and 10 mol % excess (55/55, 56/54, 58/52, and 60/50) precursor solutions by the sol–gel process. The NKN55/55 powder heat-treated at 800 °C showed an orthorhombic phase and rectangular grains whose size was estimated to be about 300 nm. With increasing Na/K ratio, grain size increased to about 1 µm and the cubic–tetragonal (Tc) phase transition peak emerged at 392 °C in a differential thermal analysis (DTA) curve. On the other hand, single-phase NKN thin films were fabricated at 600 °C from the (Na,K)-excess precursor solutions (58/52 and 60/50). In particular, the NKN58/52 thin film showed a low leakage current density (10-7 A/cm2 at 40 kV/cm), and the maximum polarization Pmax and dielectric constant εr at 1 kHz were 9.1 µC/cm2 and 725, respectively.