  The growth of atomically-flat thin films of ferroelectric PbTiO3 on SrTiO3
substrates, using molecular beam epitaxy, is reported. The main issue in the
growth of these materials is the high volatility of lead. This can be largely
overcome by using PbO, instead of Pb, as a source and by using atomic oxygen
during growth. The continuous decrease of the out-of-plane lattice parameter
with increasing temperature in the investigated range, indicates that PbTiO3 is
still ferroelectric at the growth temperature (Tg= 600oC), which agrees with
the theoretical prediction of TC= 765oC (compared to TCbulk= 490oC) for the
present mismatch strain values.
