Off-axis electron holography and microstructure of Ba0.5Sr0.5TiO3 thin film grown on LaAlO3

摘要

Epitaxial Ba0.5Sr0.5TiO3 thin films grown on the (001) LaAlO3 substrates withthe ferroelectric transition of about 250K have been investigated by TEM andoff-axis electron holography. Cross-sectional TEM observations show that the350nm-thick Ba0.5Sr0.5TiO3 film has a sharp interface with notable misfitdislocations. Off-axis electron holographic measurements reveal that, at lowtemperatures, the ferroelectric polarization results in systematicaccumulations of negative charges on the interface and positive charges on thefilm surface, and, at room temperature, certain charges could only accumulateat the interfacial dislocations and other defective areas.