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Title: Field induced modification of defect complexes in magnesium-doped lithium niobate

Dielectric constant, thermally stimulated depolarization currents (TSDC), and conductivity of undoped and 5% Mg-doped LiNbO{sub 3} single crystals between −100 °C and 200 °C have been investigated. A Debye-like dielectric relaxation with an activation energy of 135 meV is observed in the Mg-doped material, but not in undoped crystals. On heating this relaxation disappears near 140 °C and does not reappear after cooling. Anomalies observed in TSDC around this temperature are attributed to the motion of lithium vacancies, in agreement with conductivity measurements. It is proposed that in thermal equilibrium the electrons from the Mg{sub Li}{sup •} donors are trapped in (4Mg{sub Li}{sup •}+4V{sub Li}{sup ′}) defect complexes. High-temperature poling breaks these defect complexes. The transition of the liberated electrons between the Mg{sub Li}{sup •} donor centers and the Nb{sub Nb} forming the conduction band gives rise to the observed dielectric relaxation.
Authors:
;  [1] ;  [1] ;  [2]
  1. Department of Materials Research and Technology, Luxembourg Institute of Science and Technology, 41 rue du Brill, L-4422 Belvaux (Luxembourg)
  2. (France)
Publication Date:
OSTI Identifier:
22399161
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 24; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACTIVATION ENERGY; DEPOLARIZATION; DIELECTRIC MATERIALS; DOPED MATERIALS; ELECTRIC CONDUCTIVITY; ELECTRONS; HEATING; LITHIUM; LITHIUM COMPOUNDS; MAGNESIUM; MONOCRYSTALS; NIOBATES; PERMITTIVITY; RELAXATION; TEMPERATURE DEPENDENCE; THERMAL EQUILIBRIUM; TRAPPING; VACANCIES