Analysis of ac-conductivity data of Ba2−xBixF2+x solid solutions
1993; Elsevier BV; Volume: 85; Issue: 12 Linguagem: Inglês
10.1016/0038-1098(93)90159-k
ISSN1879-2766
AutoresН. Ф. Уваров, E.F. Hairetdinov, J.M. Réau, Paul Hagenmuller,
Tópico(s)Microwave Dielectric Ceramics Synthesis
ResumoAbstract Charge carriers concentrations N in the Ba 1− x Bi x F 2+ x (0⩽×⩽0.45) solid solutions were estimated from an analysis of temperature and frequency dependences of the bulk ac-conductivities. They range from 3.10 21 to 1.10 22 (cm) -3 and are temperature independent. In addition, for the (x = 0.05) sample, the parameters of NNN-dipoles are estimated as follows: the reorientation frequency is ν d = 6.10 13 exp.(-0.60 eV./kT) s -1 and the NNN-dipoles concentration is N d = 9.10 19 (cm) -3 . The comparison of the N values with the extended defect concentration estimated on the basis of the clustering model which assumes in Ba 1− x Bi x F 2+ x the progressive transformation with increasing x of 4:4:3:0 clusters into 8:12:1:0 cubooctahedral clusters, allows to propose that charge carriers governing the ionic conductivity properties are likely the interstitial fluoride ions belonging to the 4:4:3:0 clusters.
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