Quantification and mapping of elastic strains in ferroelectric [BaZrO3]xᴧ/[BaTiO3](1-x)ᴧ superlattices

Abstract

We report on quantification and elastic strain mapping in two artificial [BaZrO 3 ] xᴧ /[BaTiO 3 ] (1-x)ᴧ (BZ xᴧ /BT (1-x)ᴧ) superlattices having periods of Λ=6.6 nm and Λ = 11 nm respectively, grown on (001) SrTiO 3 single crystal substrate by pulsed laser deposition technique. The methodology consists of a combination of high-resolution scanning transmission electron microscopy and nanobeam electron diffraction associated with dedicated algorithm for diffraction patterns processing originally developed for semiconductors to record the strains at atomic scale. Both in-plane and out-of-plane elastic strains were then determined at 2 nm spatial resolution and their average values were used to map the strains along and transverse to the epitaxial growth direction of both samples to determine its variation along several BZ/BT interfaces. In addition, the variation of the width of the inter-diffusion BT/BZ interfaces and intermixing between different layers are estimated. The obtained width average value measured in these inter-diffusion interfaces vary from 8 to 12% and from 9 to 11% for both superlattices having Λ = 6.6 nm and Λ = 11 nm respectively. These inter-diffusion interfaces and the inherent elastic strains due to the confined layers of the superlattices are known to be the most important parameters, responsible of the change in their functional properties.

Strain-induced band gap tuning in flexible ferroelectric/mica thin films

“…This indicates that the B-site cations are moved from the symmetric center, and thus increasing the asymmetry of the BCTF crystal structure, which should then be favorable for retaining the intrinsic ferroelectricity. [32][33][34] It can be induced from the loops that the quality of the loop only starts to improve and to show some ferroectric activity in the film under strength. Compared with the original BCTF, the ferroelectric polarization for films with 0.85% mechanical strain increases faster at the same electric field (Fig.…”

Center Atom Model for Strain Mapping of Void and Crack of Atomic Lattice Image

“…[24,28,29] In addition, there are some postprocessing methods based on atomic coordinates, such as calculating the atomic-level elastic strain tensors in crystalline systems on the elastic-plastic decomposition of crystal deformation, [30] calculating local strain tensors based on the relative motion of neighboring particles [31,32] and using the polyhedral template matching method to calculate strain. [33] Nowadays, the most typical methods of the processing strain image are mainly represented by digital image correlation (DIC), [34][35][36][37][38][39] geometric phase approach (GPA) [27,[40][41][42][43][44] and peak pairs approach (PPA), [45][46][47] and Moiré method. [48][49][50][51] They have excellent performance and have been widely used in quantitative image characterization of the strain field in experiments.…”

Growth mode and strain effect on relaxor ferroelectric domains in epitaxial 0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3/SrRuO3 heterostructures

“…Pulsed-laser deposition (PLD) is one of the most used techniques for the epitaxial growth of a wide range of ferroic oxides and heterostructures. [33][34][35] The high volatility of lead at high deposition temperatures (usually >500 C; the temperature necessary for the formation of the perovskite phase) promotes the formation of the pyrochlore phases which results in high leakage currents, among other effects. Using PLD, different strategies have been considered to minimize the evaporation of lead at high temperatures and to produce pure PMN-PT lms.…”