【摘要】 缓冲层作为一种调控铁电薄膜畴组态和引入新的微结构的有效手段被广泛采用。本文在大拉应变KTaO₃衬底上生长了LaNiO₃/PbTiO₃多层膜,利用透射电子显微学方法,对该薄膜体系中的缺陷结构及其与铁电畴的交互作用进行了细致地研究。结果表明,由于巨大的界面失配,LaNiO₃层中形成密集的Ruddlesden-Popper型层错,该层错经由LaNiO₃/PbTiO₃异质界面诱导PbTiO₃中形成贯穿型的层状缺陷,这种缺陷的形成对PbTiO₃内部畴结构有着一定的影响。利用电子能量损失谱,发现层状缺陷处Ti元素的价态有所降低,可能源于LaNiO₃与PbTiO₃之间的电荷传递。这一结果揭示了中间缓冲层对PbTiO₃薄膜内部微结构产生重要的影响,同时也为铁电畴的调控提供了新的途径。更多还原

【Abstract】 Buffer layer is widely used as an effective method to modulate domain configuration and introduce new microstructures in ferroelectric thin films. In this paper, a LaNiO₃/PbTiO₃ multilayer film was grown on the large tensile strain KTaO₃ substrate. The defect structures of the film system and the interaction between defects and ferroelectric domains were investigated by using transmission electron microscopy（TEM）. The results show that dense Ruddlesden-Popper（R-P） faults are formed in the LaNiO₃ layer due to the large lattice mismatch, which induces the formation of penetrating layered defects in PbTiO₃ across the LaNiO₃/PbTiO₃ heterogeneous interface. The formation of such defects has a certain influence on the internal domain structure of PbTiO₃ layer. It was further found that the valence state of Ti ions decreased at the layered defect by using electron energy loss spectrum, which might be attributed to the charge transfer between LaNiO₃ and PbTiO₃ layers. These results reveal that the intermediate buffer layer has an important effect on the microstructure of PbTiO₃ films and provides a new way to modulate the ferroelectric domain configurations.更多还原