Polar domains in lead titanate films under tensile strain
  Thin films of PbTiO3, a classical ferroelectric, have been grown under tensile strain on single-crystal substrates of DyScO3. The films, of only 5nm thickness, grow fully coherent with the substrate and show no crystallographic twin domains, as evidenced by synchrotron x-ray diffraction. A mapping of the reciprocal space reveals intensity modulations (satellites) due to regularly-spaced polar domains in which the polarization appears rotated away from the substrate normal, characterizing a low symmetry phase not observed in the bulk material. This could have important practical implications since these phases are known to be responsible for ultrahigh piezoelectric responses in complex systems. 
G. Catalan, A. Janssens, G. Rispens, S. Csiszar, O. Seeck, G.   Rijnders, D.H.A. Blank, B. Noheda