ULTRA-THIN LEAD TITANATE FILMS GROWN BY MOLECULAR BEAM EPITAXY

ABSTRACT

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 (RT-650?C), indicates that the films are still ferroelectric at the growth temperature (Tg = 600?C), as expected according to the theoretical prediction of TC = 765?C (compared to T^bulk _C = 490?C) for the present mismatch strain values.

ACKNOWLEDGMENTS

We would like to thank Henk Bruinenberg for his valuable technical assistance and Gustau Catalan, Szilard Csiszar, Tjipke Hibma and Ard Vlooswijk for useful discussions. This work is part of the research programme of the ‘Stichting voor Fundamenteel Onderzoek der Materie (FOM)’, which is financially supported by the ‘Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)’.