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, α∼0.3, and the value increased continuously during cooling, and eventually the c-domain dominant structure (α∼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.