Atomic structure and microstructures of supertetragonal multiferroic BiFeO3 thin films

We revisit the atomic structure and microstructure of the so-called supertetragonal phases of highly strained epitaxial BiFeO3 thin films. Quantitative atomic resolution scanning transmission electron microscopy is used to directly image the atomic positions. A crystallographic phase suggested by electron diffraction and predicted by ab initio calculations is evidenced. Microtwins are reported in thickest films. Electron energy loss …