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Phase transition associated with the variation of oxygen vacancy/ion distribution in the oxide‐ion conductor La 2 Mo 2– x W x O 9
Author(s) -
Li D.,
Wang X. P.,
Fang Q. F.,
Wang J. X.,
Li C.,
Zhuang Z.
Publication year - 2007
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200622498
Subject(s) - tungsten , ion , dielectric , doping , analytical chemistry (journal) , vacancy defect , diffusion , relaxation (psychology) , materials science , activation energy , oxygen , phase (matter) , chemistry , crystallography , thermodynamics , physics , psychology , social psychology , optoelectronics , organic chemistry , chromatography , metallurgy
The effects of tungsten doping in La 2 Mo 2– x W x O 9 samples ( x = 0, 0.1, 0.25, 0.5, 0.75, 1.0, 1.2, 1.4) were studied using dielectric relaxation measurements. Additional to the low‐temperature relaxation peak P d associated with oxygen ion diffusion, a new dielectric loss peak P h was observed around 740 K. With increasing tungsten concentration, the activation energy of peak P d increases and saturates at a value of about 1.45 eV, and the height of peak P h increases at first and then decreases after passing a maximum at 25% tungsten doping. With increasing measurement frequency, the height of peak P h decreases monotonically but its position shifts very little. Peak P h in pure and tungsten‐doped La 2 Mo 2 O 9 is suggested to be associated with a phase transition from the static disordered state to the dynamic disordered state of oxygen ion/vacancy distribution. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)