Studies of two distinct types of (Ba,Sr)TiO3∕Pt interfaces

High resolution transmission electron microscopy is used to investigate the interfacial layer at interfaces between (001) (Ba,Sr)TiO3 (BST) films and (111) Pt electrodes. Two distinct types of interfaces are observed. One case is the presence of interfacial layer with distorted structure, whereas another case is the good interfacial match without any interfacial layer. Based on the analyses of crystallographic relationships between BST and Pt, it is proposed that the in-plane lattice structure plays an important role in determining the feature of the interface. The impact of A-O and B-O terminations of BST films on the interfacial layer is also discussed.