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Title: Temperature dependent near infrared ultraviolet range dielectric functions of nanocrystalline (Na{sub 0.5}Bi{sub 0.5}){sub 1−x}Ce{sub x}(Ti{sub 0.99}Fe{sub 0.01})O{sub 3} films

Optical properties and phase transition of Ce-modified (Na{sub 0.5}Bi{sub 0.5})(Ti{sub 0.99}Fe{sub 0.01})O{sub 3} nanocrystalline films have been investigated by spectroscopic ellipsometry from −70 to 500 °C. Temperature dependent dielectric functions in the photon energy range of 0.6–6.4 eV can be derived by the Tauc-Lorentz model. It was found that the features in dielectric function (ε) showed an abrupt variation near 200 and 340 °C, respectively. The phenomena can be explained by the appearance and/or reversal of polarization. It indicates that ferroelectric (rhombohedral) to paraelectric (tetragonal) phase transition is related to electronic band variation, which is observed by this technique.
Authors:
; ; ; ; ;  [1]
  1. Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China)
Publication Date:
OSTI Identifier:
22280555
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 77 NANOSCIENCE AND NANOTECHNOLOGY; BISMUTH COMPOUNDS; CERIUM COMPOUNDS; CRYSTALS; ELLIPSOMETRY; EV RANGE; FERROELECTRIC MATERIALS; IRON COMPOUNDS; NANOSTRUCTURES; OPTICAL PROPERTIES; PERMITTIVITY; PHASE TRANSFORMATIONS; POLARIZATION; SODIUM COMPOUNDS; TEMPERATURE DEPENDENCE; TETRAGONAL LATTICES; THIN FILMS; TITANATES; TRIGONAL LATTICES; ULTRAVIOLET RADIATION; VARIATIONS