Bulk conductivity and polarization of ionic crystals exhibiting defect exchange between inequivalent sites

Franceschetti, Donald R.; Shipe, Paul C.

doi:10.1016/0167-2738(84)90018-3

Cited by 17 publications

(7 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These new conduction pathways are formed due to the different crystal orientation of the film (LF4) which is observed in XRD analysis. This type of anisotropy in the F À ionic conductivity of LaF 3 single crystals has been reported previously [11]. Normally the LaF 3 material has three possible sites (F 1 , F 2 , F 3 ) for the F À ion movement.…”

Section: Conductivity Analysismentioning

confidence: 74%

Structural and impedance studies on LaF3 thin films prepared by vacuum evaporation

Vijayakumar

Selvasekarapandian

Gnanasekaran

et al. 2004

Journal of Fluorine Chemistry

View full text Add to dashboard Cite

Section: Conductivity Analysismentioning

confidence: 74%

Structural and impedance studies on LaF3 thin films prepared by vacuum evaporation

Vijayakumar

Selvasekarapandian

Gnanasekaran

et al. 2004

Journal of Fluorine Chemistry

View full text Add to dashboard Cite

“…4), we conclude that the association model fails to describe satisfactorily our experimental results. On the other hand, the aforementioned exchange model of Franceschetti and Shipe [28] can be used to describe the experimental observations adequately. With P3 = 0 and the NMR values for jump frequencies and activation enthalpies [24,25 ], we have calculated a theoretical log oT versus lIT plot (see fig.…”

Section: Intermediate Region: 0 < X < ~7 X 10 -2 (Samplesmentioning

confidence: 99%

“…The bulk small-signal ac response of LaF 3 has been calculated theoretically, using the standard thermally activated form for jump probabilities. Their analysis leads to the following equation for the high-frequency bulk resistance [28] tration of anion vacancies, A the cross sectional area, and a and b are the jump distances indicated in fig. 6.…”

Section: "Pure"laf 3 (Samples 1 and 2)mentioning

confidence: 99%

See 1 more Smart Citation

Ionic conductivity in tysonite-type solid solutions La1−xBaxF3−x

et al. 1984

View full text Add to dashboard Cite

The ionic conductivity of single crystals of tysonite-type solid solutions Lal_xBaxFa_x(O • x • 0.095) has been studied parallel and perpendicular to the crystallographic c axis in the temperature range 293-1300 K. Three regions can be discerned in the compositional dependence of the ionic conductivity: (i) the "pure" crystal, in which at room temperature no exchange occurs between different types of anion sites in the tysonite structure; (ii) an intermediate region (0 < x < 7 X 10 -2) which reveals changes in both the conductivity activation enthalpy and the magnitude of the conductivity; (iii) a concentrated solid-solution region (x > 7 X 10-2), where fluoride ions interchange easily among the different anion sublattices. Diffusion coefficients calculated from ionic conductivity results, are in good agreement with those calculated from 19F NMR measurements. Using the present data, along with 19F NMR data, dielectric relaxation data and structural considerations, mechanisms governing the ionic conductivity are proposed.

show abstract

“…Even if one treats the Fz and F3 sites as equivalent, at least three different kinds of anion jump are possible: F,-FI, F,-FZ and F2-F2. A model has now been developed [8] for the smallsignal bulk ac response of tysonite type materials which does lead to a Debye-type of equivalent circuit without the assumed presence of dipolar complexes. In examining a model of the tysonite structure one finds that in the direction of the c axis, and in the direction of the bisector of the a and b axes, the lattice planes occur in the pattern AABAAB, where "A" denotes a plane containing only F1 type fluoride sites and "B" denotes a plane containing F2 and F3 type sites, here treated as equivalent.…”

Section: Discussionmentioning

confidence: 99%

The small-signal ac response of La1−xBaxF3−x solid solutions

1984

Self Cite

View full text Add to dashboard Cite

The small-signal ac response of single crystals of La,_,Ba,F,_, (0 s x G 0.104) with ionically blocking electrodes has been measured in the frequency range lo-* to 10' Hz, and for temperatures from 293 to 1300 K. At low and moderate temperatures the ac bulk response can be modeled with a Debye circuit. The circuit parameters do not have the temperature dependence associated with dipolar reorientation but rather the opposite, as is characteristic of the behavior of free charge carriers. We have developed a model, in which the theoretically expected dependence of the circuit parameters is concordant to the behavior found experimentally. Thermally stimulated depolarization current (TSDC) spectra exhibit five dielectric relaxation peaks, in addition to a space-charge peak. Two peaks have been analyzed in detail. The reorientation enthalpies are concordant with the conduction activation enthalpies.La rtponse signal-faible par courant altematif de monocrystaux du type La,_,Ba,F,_, (0 G x s 0.104) avec des electrodes de blocage des ions a tti mesuree dans le domaine de frequence lo-' a lo5 Hz, et pour des temperatures entre 293 et 1300 K. A des temperatures basses et modtrees la reponse du volume par courant alternatif put &re represent6 a l'aide du circuit Debye. Les parambtres du circuit ne montrent pas la dtpendance de temperature associee a la reorientation dipolaire mais plut& l'oppost, ce qui est caracttristique du comportement des porteurs de charge libre. Nous avons dtvelopp6 un modtle oh la dependance attendu theoriquement des parametres du circuit s'accorde avec le comportement trouvt en experiment. Thermally stimulated depolarization current (TSDC) spectres montrent cinq pits de relaxation dielectrique et en plus un pit de charge d'espace. Deux pits ont BtC analysts en detail. Les enthalpies de reorientation s'accordent avec les enthalpies de l'activation de la conduction.

show abstract

Bulk conductivity and polarization of ionic crystals exhibiting defect exchange between inequivalent sites

Cited by 17 publications

References 7 publications

Structural and impedance studies on LaF3 thin films prepared by vacuum evaporation

Structural and impedance studies on LaF3 thin films prepared by vacuum evaporation

Ionic conductivity in tysonite-type solid solutions La1−xBaxF3−x

The small-signal ac response of La1−xBaxF3−x solid solutions

Contact Info

Product

Resources

About