%0 Journal Article %K Transmission electron microscopy %K Polarization %K Ferroelectric materials %K Polarization switching %K Scanning transmission electron microscopy %K Ab initio calculations %K High resolution scanning %K High-angle annular dark fields %K Local atomic structures %K Local polarization %A A Lubk %A M.D Rossell %A J Seidel %A Q He %A S.Y Yang %A Y.H Chu %A Ramamoorthy Ramesh %A M.J Hÿtch %A E Snoeck %B Physical Review Letters %D 2012 %G eng %R 10.1103/PhysRevLett.109.047601 %T Evidence of sharp and diffuse domain walls in BiFeO 3 by means of unit-cell-wise strain and polarization maps obtained with high resolution scanning transmission electron microscopy %V 109