Liquid–solid directional composites and anisotropic dipolar phases of polar nanoregions in disordered perovskites. Issue 27 (30th June 2017)

• Record Type: Journal Article
• Authors: Parravicini, Jacopo; DelRe, Eugenio; Agranat, Aharon J.; Parravicini, Gianbattista
• Is Part Of: Nanoscale. Volume 9:Issue 27(2017)
• Page Start: 9572
• Page End: 9580
• Publication Date: 2017-06-30
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c6nr09817g
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : An exotic liquid–solid composite state of polar nanoregions, with a liquid-like response along specific directions and simultaneously solid-like along others. Abstract : Using temperature-resolved dielectric spectroscopy in the range of 75–320 K we have inspected the solid-like and liquid-like arrangements of nanometric dipoles (polar nanoregions) embedded in sodium-enriched potassium-tantalate-niobate (KNTN), a chemically-substituted complex perovskite crystal hosting inherent substitutional disorder. The study of order versus direction is carried out using Fröhlich entropy measurements and indicates the presence of four long-range symmetry phases, two of which are found to display profoundly anisotropic features. Exotic phases are found for which the dipoles at one fixed temperature manifest a liquid reorientational response along one crystal axis and a solid-like behavior along another axis. The macroscopic anisotropy observed in the sequence of different phases is found to match a microscopic order–disorder sequence typical of nominally pure perovskites. Moreover, experimental demonstration of the onset of a frozen state above transitions is provided.