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Title: Mixed conduction and grain boundary effect in lithium niobate under high pressure

The charge transport behavior of lithium niobate has been investigated by in situ impedance measurement up to 40.6 GPa. The Li{sup +} ionic conduction plays a dominant role in the transport process. The relaxation process is described by the Maxwell-Wagner relaxation arising at the interfaces between grains and grain boundaries. The grain boundary microstructure rearranges after the phase transition, which improves the bulk dielectric performance. The theoretical calculations show that the decrease of bulk permittivity with increasing pressure in the Pnma phase is caused by the pressure-induced enhancement of electron localization around O atoms, which limits the polarization of Nb-O electric dipoles.
Authors:
 [1] ;  [2] ; ; ;  [1] ;  [1] ;  [3] ;  [4]
  1. State Key Laboratory of Superhard Materials, Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China)
  2. (China)
  3. (United States)
  4. Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)
Publication Date:
OSTI Identifier:
22398826
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 13; Other Information: (c) 2015 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; ATOMS; CHARGE TRANSPORT; DIELECTRIC MATERIALS; ELECTRIC DIPOLES; ELECTRONS; GRAIN BOUNDARIES; IMPEDANCE; INTERFACES; LITHIUM COMPOUNDS; LITHIUM IONS; NIOBATES; ORTHORHOMBIC LATTICES; PERMITTIVITY; PHASE TRANSFORMATIONS; POLARIZATION; PRESSURE DEPENDENCE; PRESSURE RANGE GIGA PA; RELAXATION