Local structure of relaxor ferroelectric Sr.sub.x./sub.Ba.sub.1-x./sub.Nb.sub.2./sub.O.sub.6./sub. from a pair distribution function analysis

0519366 - FZÚ 2020 RIV US eng J - Journal Article
Pasciak, Marek - Ondrejkovič, Petr - Kulda, J. - Vaněk, Přemysl - Drahokoupil, Jan - Steciuk, Gwladys - Palatinus, Lukáš - Welberry, T.R. - Fischer, H. E. - Hlinka, Jiří - Buixaderas, Elena
Local structure of relaxor ferroelectric Sr_xBa_1-xNb₂O₆ from a pair distribution function analysis.
Physical Review B. Roč. 99, č. 10 (2019), s. 1-12, č. článku 104102. ISSN 2469-9950. E-ISSN 2469-9969
R&D Projects: GA ČR GA16-09142S
Institutional support: RVO:68378271
Keywords : relaxor ferroelectrics * disorder * pair distribution function analysis
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 3.575, year: 2019
Method of publishing: Limited access
https://doi.org/10.1103/physrevb.99.104102

Pair distribution function analysis of neutron-scattering data and of ab initio molecular dynamics results have been employed to study short-range order and its temperature dependence in a disordered dielectric material SrxBa1−xNb2O6(x=0.35,0.5, and 0.61). Intrinsic disorder of Sr and Ba atoms and their vacancies introduces local strains to the structure and influences the Nb-O6 octahedra tilting. The resulting complex system of tilts is found to be both temperature and Sr-doping sensitive with the biggest tilt magnitudes reached at low temperatures and high strontium contents, where ferroelectric relaxor behavior appears. We find evidence for two Nb-O6 subsystems with different variations of niobium-oxygen bond lengths, distinct dynamics, and disparate levels of deviation from macroscopic polarization direction. These findings establish a detailed picture of the local structure of SrxBa1−xNb2O6 and provide a deeper insight into the origins of the materials dielectric properties.
Permanent Link: http://hdl.handle.net/11104/0304360