Abrupt PbTiO3/SrTiO3 superlattices grown by reactive molecular beam epitaxy

PbTiO3/SrTiO3 superlattices were grown on (001) SrTiO3 substrates by reacti ve molecular beam epitaxy (MBE). Sharp superlattice reflections were observ ed by x-ray diffraction. High-resolution transmission electron microscopy o f a [(PbTiO3)(10)/(SrTiO3)(10)](15) superlattice revealed that the PbTiO3/S rTiO3 interface structure is atomically sharp. The superlattice interfaces are fully coherent; no misfit dislocations or other crystal defects were ob served in the superlattice by transmission electron microscopy. Selected ar ea electron diffraction patterns indicated that the PbTiO3 layers are orien ted with the c axis parallel to the growth direction. The dimensional contr ol and interface abruptness achieved in this model system indicate that MBE is a viable method for constructing oxide multilayers on a scale where enh anced dielectric effects are expected. (C) 1999 American Institute of Physi cs. [S0003-6951(99)02919-8].