Publication Type:Journal Article
Source:Applied Physics Letters, Volume 85, Number 18, p.4109-4111 (2004)
Keywords:Barium compounds, Epitaxial constraints, Epitaxial growth, Ferroelectric instability, Ferroelectric materials, Ferroelectric phase transition, heat treatment, High temperature effects, lattice constants, phase transitions, Structural phase transition, thin films
For (001) coriented BaTiO 3 thin films, it has been found that epitaxial constraint can result in a dramatic increase in the temperature of a tetragonal (T) structural phase transition. For 2000-Å-thick films grown directly on SrTiO 3 substrates, a T → cubic (C) phase transition was found on heating at >950 K, where the lattice constant changed smoothly with temperature. It was also found for films of the same thickness that the T → C transition is nearly restored to that of bulk crystals by the use of a buffer layer, which relaxes the epitaxial constraint. These results provide evidence of an epitaxially induced high temperature structural phase transition in BaTiO 3thin films, where the ferroelectric (internal) and structural (external) aspects of the phase transition are decoupled. © 2004 American Institute of Physics.
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