Misfit dislocations in nanoscale ferroelectric heterostructures

Nagarajan, V.; Waser, R.; Misirlioglu, I. B.; Ramesh, R.; Alpay, S. P.; Kohlstedt, H.; Jia, C. L.

doi:10.1063/1.1922579

Journal Article

Misfit dislocations in nanoscale ferroelectric heterostructures

Nagarajan, V. ; Jia, C. L.FZJ* ; Kohlstedt, H.FZJ* ; Waser, R.FZJ* ; Misirlioglu, I. B. ; Alpay, S. P. ; Ramesh, R.

2005
American Institute of Physics Melville, NY

Applied physics letters 86, 192910 (2005) [10.1063/1.1922579]

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Please use a persistent id in citations: http://hdl.handle.net/2128/1096 doi:10.1063/1.1922579

Abstract: We present a quantitative study of the thickness dependence of the polarization and piezoelectric properties in epitaxial (001) PbZr0.52Ti0.48O3 films grown on (001) SrRuO3-buffered (001) SrTiO3 substrates. High-resolution transmission electron microscopy reveals that even the thinnest films (similar to 8 nm) are fully relaxed with a dislocation density close to 10(12) cm(-2) and a spacing of approximately 12 nm. Quantitative piezoelectric and ferroelectric measurements show a drastic degradation in the out-of-plane piezoelectric constant (d(33)) and the switched polarization (DP) as a function of decreasing thickness. In contrast, lattice-matched ultrathin PbZr0.2Ti0.8O3 films that have a very low dislocation density show superior ferroelectric properties. Supporting theoretical calculations show that the variations in the strain field around the core of the dislocation leads to highly localized polarization gradients and hence strong depolarizing fields, which result in suppression of ferroelectricity in the vicinity of a dislocation. (c) 2005 American Institute of Physics.

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