Roadmap for space group construction of an isovalent modified perovskite based on electron diffraction data

Polar orientation and extension in a novel crystallographic model for PbTiO3-based perovskites explaining the experimental ferroelectric thermal anomalies

“…By applying a Pearson profile function, it was possible to find many space groups with the same figure of merit and choose the best model that fitted two small peaks between 25.25 and 25.45 � , which originate from the octahedral tilting. Considering additional information on the screw axis observed using convergent-beam electron diffraction for the compound PCT47.5 in previous reports (Estrada et al, 2014;Estrada & Garcia, 2021), the space group Pna2 1 was chosen as the best model to fit the roomtemperature PCT45 XRD pattern. The atomic positions were determined by direct methods (Altomare et al, 2004).…”

“…The discovery of the structural origin of the high piezoelectric performance of PbTiO 3 -based materials by Noheda and collaborators (Guo et al, 2000;Noheda et al, 1999;Noheda & Cox, 2006) changed the scenario and opened the discussion to different space groups and new structural models to explain ferroelectricity in perovskites (Stokes et al, 2002;Senn & Bristowe, 2018;Capillas et al, 2004;Kroumova et al, 2002;Zhang et al, 2023;Wang et al, 2022), giving rise to a series of phase diagram revisions in search of the 'missing boundary' found for Pb(Zr,Ti)O 3 (Zhang et al, 2014;An et al, 2021), (Ba,Sr)TiO 3 (Wang et al, 2018) and many other solidsolution systems (Ribeiro Gala ˜o et al, 2022;Li et al, 2021;Estrada et al, 2021;Chen, 2000;Phelan et al, 2015).…”