Lead-free Na0.5Bi0.5TiO3 ferroelectric thin films grown by Pulsed Laser Deposition on epitaxial platinum bottom electrodes
Lead-free Na0.5Bi0.5TiO3 ferroelectric thin films grown by Pulsed Laser Deposition on epitaxial platinum bottom electrodes
复制标题
DOI：
10.1016/j.tsf.2008.06.088
复制
发表时间：
2008-11
期刊：
影响因子：
2.1
通讯作者：
J. Duclère;C. Cibert;A. Boulle;V. Dorcet;P. Marchet;C. Champeaux;A. Catherinot;S. Députier;
中科院分区：
文献类型：
--
作者：
J. Duclère;C. Cibert;A. Boulle;V. Dorcet;P. Marchet;C. Champeaux;A. Catherinot;S. Députier;
通过脉冲激光沉积在 c 蓝宝石衬底支撑的外延 (111)Pt 层上生长无铅 Na{sub 0.5}Bi{sub 0.5}TiO{sub 3} 薄膜。 X 射线衍射证明了三种不同生长方向（即（100）、（110）和（111）之间的竞争。与每个生长方向相对应的摇摆曲线值是从倒易空间映射测量得出的。 X射线{phi}扫描数据表明，只有(111)取向的Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}微晶外延生长到(111)Pt底部电极上，而在(100)取向微晶的情况下发生织构生长。为了解释生长行为的这种差异，提供了 (111)Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}/(111)Pt 界面的近重合位点晶格模型。还讨论了 (100)Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}/(111)Pt 界面的性质。此外，室温磁滞回线证明了精心设计的材料的铁电活性。对于 126 kV/cm 的相应矫顽场，剩余极化高达 15.9 {mu}C/cm{sup 2}。最后，疲劳数据表明极化幅度仅小幅下降，这反映在 6.10{sup 9} 切换周期后，+P* 和 -P* 参数分别下降 15% 和 12%。因此，这种原始Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}/Pt/c-Al{sub 2}O{sub 3}异质结构的极化幅度的轻微降低可以与沉积在Pt电极上的PbZr{sub 1-x}Ti{sub x}O{sub 3}薄膜观察到的疲劳效应相媲美。
Lead-free Na{sub 0.5}Bi{sub 0.5}TiO{sub 3} thin films were grown by Pulsed Laser Deposition on an epitaxial (111)Pt layer supported by a c-sapphire substrate. A competition between three different growth orientations, namely (100), (110) and (111), was evidenced by X-ray diffraction. The rocking-curve values corresponding to each growth orientation were derived from the reciprocal space mapping measurements. The X-ray {phi}-scan data indicate that only the (111)-oriented Na{sub 0.5}Bi{sub 0.5}TiO{sub 3} crystallites epitaxially grow onto (111)Pt bottom electrode, whereas a textured growth occurs in the case of (100)-oriented crystallites. In order to explain such difference in the growth behaviour, a near coincidence site lattice model of the (111)Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}/(111)Pt interface is provided. The nature of the (100)Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}/(111)Pt interface is also discussed. In addition, the room temperature hysteresis loops testify to the ferroelectric activity of the elaborated materials. The remanent polarization goes up to 15.9 {mu}C/cm{sup 2}, for a corresponding coercive field of 126 kV/cm. Finally, the fatigue data indicate only a small reduction in the polarization amplitude, reflected by the decrease of 15% and 12% of both +P* and -P* parameters, respectively, after 6.10{sup 9} switching cycles. This slight decrease in the polarization amplitude for such original Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}/Pt/c-Al{sub 2}O{sub 3} heterostructures can thus be compared favourably to the fatigue effects observed for PbZr{sub 1-x}Ti{sub x}O{sub 3} thin films deposited on Pt electrodes.