Study on Ca Segregation toward an Epitaxial Interface between Bismuth Ferrite and Strontium Titanate U. Haselmann, G. Haberfehlner, W. Pei, M. Popov, L. Romaner, D. Knez, J. Chen, A. Ghasemi, Y. He, G. Kothleitner, Z. Zhang ACS Appl. Mater. Interfaces12, 12264-12274 (2020)