Reciprocal space mapping of phase transformation in epitaxial PbTiO3 thin films using synchrotron x-ray diffraction

Phase transformation in epitaxial PbTiO3 thin films grown on MgO(001) substrates was studied and quantified by two-dimensional reciprocal space mapping technique using synchrotron x-ray diffraction equipped with an in situ high temperature stage. Just below the Curie temperature, a twin-like domain structure was formed with an initial value of c-domain abundance, alpha similar to 0.3, and the value increased continuously during cooling, and eventually the c-domain dominant structure (alpha similar to 0.72) was achieved at room temperature through continuous expansion of the c domains. By investigating the intensity distribution of contour maps, domain tilting and mosaicity were characterized along the q([h00]) direction and the presence of a strain gradient along the growth direction q([001]) was also confirmed from the asymmetric distribution of the contour maps. (C) 1999 American Institute of Physics. [S0021-8979(99)03403-9].