BiFeO_(3)外延薄膜的自极化调控

Self-polarization Modulation of BiFeO_(3) Epitaxial Films

通过对衬底/底电极界面行为的研究,发现界面效应可以调控BiFeO_(3)外延薄膜的自极化.由于底电极和薄膜均具有钙钛矿类型的结构,通过改变衬底/底电极的界面类型和阴/阳离子层排列方式,可以在BiFeO_(3)/SrRuO_(3)(La_(0.67)Sr_(0.33)MO_(3))/SrTiO_(3)异质结构中获得两种不同类型的界面.实验结果表明BFO薄膜在SrTiO_(3)衬底上共格生长,且两种异质结薄膜呈向上/向下的内建电场E_(b)和c-畴180°翻转.这些研究结果揭示了不同底电极选择导致的异质结构界面处的电荷分布与内建电场方向的差异,为调控异质结性能提供了一种可选途径.

Through the investigation of the substrate/bottom electrode interface behavior,it is discovered that interface effects can modulate the polarization of BiFeO_(3) epitaxial films.As both the bottom electrode and the film possess perovskite-type structures,by altering the interface layer type and position of the substrate/bottom electrode,two different types of interfaces can be achieved in the BFO/SRO(LSMO)/STO heterostructure.XRD and RSM characterizations indicate that the BFO film grows epitaxially on the STO substrate.Combined with PFM characterization,the two heterostructure films exhibit upward/downward spontaneous polarization(E_(b))and c-domain 180°flipping.These research findings reveal differences in charge distribution and the direction of the built-in electric field at the interface of heterostructures caused by different choices of bottom electrodes,providing new strategies for modulating the performance of heterostructure devices.