Structural characterization of BaTiO3 thin films grown by molecular beam epitaxy

Abstract

Crystallographic and microstructural studies of BaTiO3 thin films grown on SrTiO3 by laser molecular beam epitaxy J. Vac. Sci. Technol. A 15, 275 (1997); 10.1116/1.580524 BaTiO3 thin films grown on SrTiO3 substrates by a molecular-beam-epitaxy method using oxygen radicals Epitaxial ultrathin films of BaTiO 3 were prepared using molecular beam epitaxy. For the substrate, ͑001͒-oriented SrTiO 3 single crystals were used. Controlling the growth conditions of these films as well as the semiconductor thin films, led to the successful growth of the BaTiO 3 films as single crystals, characterized by x-ray diffraction even in the ultrathin range. The ultrathin BaTiO 3 films are highly c-axis-oriented tetragonal phaselike bulk BaTiO 3 crystals. The tetragonality of the thin film crystals is much larger than bulk crystal's. We also measured the saturated polarization ( Ps͒ of the BaTiO 3 films at temperatures ranging from room temperature to 600°C. The results confirmed again that the films are ferroelectric tetragonal phase crystals. Moreover, they showed that the transition temperature for the ferroelectric-paraelectric phase transition of the films is higher than bulk crystal's.

Lattice screening of the polar catastrophe and hidden in-plane polarization in KNbO3/BaTiO3interfaces

“…52 In particular, when KNbO 3 or BaTiO 3 thin films are grown on top of a SrTiO 3 substrate, the in-plane polarization of these materials vanishes and the tetragonal c phase is stabilized. 60,61 However, contrary to current thought, in our calculations of the BaTiO 3 /KNbO 3 interfaces, we can observe in Fig. 3 the appearance of a moderate in-plane polarization in these systems along the [110] direction.…”

Properties of epitaxial (110) BaTiO3films from first principles

“…In particular, there have been a lot of calculations and experimental works devoted to epitaxial thin films made of the prototype BaTiO 3 (BTO) ferroelectric . [3][4][5][6][7][8][9] As a result, novel features have been reported in these nanostructures. For instance, FE thin films under short-circuit-like electrical boundary conditions (for which the depolarizing field vanishes or is rather small, as a result of a large screening of the polarization-induced surface charges) exhibit different directions for the spontaneous polarization and different resulting crystallographic phases, depending on the misfit strain arising from the substrate on top of which the film is grown.…”

Ab initiostudy of the phase diagram of epitaxialBaTiO3

“…While many factors are expected to contribute to these differences, it has been shown that the properties of perovskite thin films are strongly influenced by the magnitude of the epitaxial strain resulting from latticematching the film to the substrate. For example, Yoneda et al [4] used molecular-beam epitaxy (MBE) to grow BaTiO 3 (lattice constant of 4.00Å) on (001)-oriented SrTiO 3 (lattice constant of 3.91Å); they found that the ferroelectric transition temperature exceeds 600 • C, to be compared to the bulk Curie temperature of T C = 130 • C. Other studies have shown that the amount of strain in BaTiO 3 /SrTiO 3 superlattices on SrTiO 3 substrates strongly influences properties including the observed polarization, phase transition temperature, and dielectric constant [5,6,7,8].…”