Details
| Original language | English |
|---|---|
| Pages (from-to) | 1016-1021 |
| Number of pages | 6 |
| Journal | Defect and Diffusion Forum |
| Volume | 237-240 |
| Issue number | PART 2 |
| Publication status | Published - 2005 |
Abstract
Impedance spectroscopy was employed to investigate the Li ion diffusivity in single crystal, microcrystalline, nanocrystalline and amorphous lithium niobate (LiNbO3). Nanocrystalline LiNbO3 with different grain sizes was prepared by high-energy ball milling from the microcrystalline starting material. The amorphous form was prepared by a double alkoxide (sol-gel) route. The frequency dependent conductivity was measured under oxygen atmosphere at frequencies, ω/2π, ranging from 5 Hz to 13 MHz. The ionic conductivity at, e.g., 450 K was found to increase by about seven orders of magnitude by going from the single crystal through the microcrystalline to the corresponding nanocrystalline and amorphous forms. The increased free volume in the amorphous material could be responsible for the enhanced conductivity, whereas in nanocrystalline LiNbO3 the behavior is governed by the increased fraction of the interfacial regions which are highly disordered and may in the present case be visualized as amorphous. In all cases the frequency dependence of the real part of the conductivity can be represented by a power law and can be scaled to give master curves. Impedance data were analyzed in the complex plane plot (with ω as implicit parameter). Both the dc conductivity and the relaxation frequency of the impedance arc, ωr/2π were found to follow Arrhenius behaviour with similar activation energies.
Keywords
- Amorphous, Conductivity, Impedance spectroscopy, Lithium diffusion, Lithium niobate, Nanocrystalline ceramics
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Radiation
- Materials Science(all)
- Physics and Astronomy(all)
- Condensed Matter Physics
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In: Defect and Diffusion Forum, Vol. 237-240, No. PART 2, 2005, p. 1016-1021.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Impedance spectroscopy study of Li ion dynamics in single crystal, microcrystalline, nanocrystalline, and amorphous LiNbO3
AU - Masoud, Muayad
AU - Heitjans, Paul
PY - 2005
Y1 - 2005
N2 - Impedance spectroscopy was employed to investigate the Li ion diffusivity in single crystal, microcrystalline, nanocrystalline and amorphous lithium niobate (LiNbO3). Nanocrystalline LiNbO3 with different grain sizes was prepared by high-energy ball milling from the microcrystalline starting material. The amorphous form was prepared by a double alkoxide (sol-gel) route. The frequency dependent conductivity was measured under oxygen atmosphere at frequencies, ω/2π, ranging from 5 Hz to 13 MHz. The ionic conductivity at, e.g., 450 K was found to increase by about seven orders of magnitude by going from the single crystal through the microcrystalline to the corresponding nanocrystalline and amorphous forms. The increased free volume in the amorphous material could be responsible for the enhanced conductivity, whereas in nanocrystalline LiNbO3 the behavior is governed by the increased fraction of the interfacial regions which are highly disordered and may in the present case be visualized as amorphous. In all cases the frequency dependence of the real part of the conductivity can be represented by a power law and can be scaled to give master curves. Impedance data were analyzed in the complex plane plot (with ω as implicit parameter). Both the dc conductivity and the relaxation frequency of the impedance arc, ωr/2π were found to follow Arrhenius behaviour with similar activation energies.
AB - Impedance spectroscopy was employed to investigate the Li ion diffusivity in single crystal, microcrystalline, nanocrystalline and amorphous lithium niobate (LiNbO3). Nanocrystalline LiNbO3 with different grain sizes was prepared by high-energy ball milling from the microcrystalline starting material. The amorphous form was prepared by a double alkoxide (sol-gel) route. The frequency dependent conductivity was measured under oxygen atmosphere at frequencies, ω/2π, ranging from 5 Hz to 13 MHz. The ionic conductivity at, e.g., 450 K was found to increase by about seven orders of magnitude by going from the single crystal through the microcrystalline to the corresponding nanocrystalline and amorphous forms. The increased free volume in the amorphous material could be responsible for the enhanced conductivity, whereas in nanocrystalline LiNbO3 the behavior is governed by the increased fraction of the interfacial regions which are highly disordered and may in the present case be visualized as amorphous. In all cases the frequency dependence of the real part of the conductivity can be represented by a power law and can be scaled to give master curves. Impedance data were analyzed in the complex plane plot (with ω as implicit parameter). Both the dc conductivity and the relaxation frequency of the impedance arc, ωr/2π were found to follow Arrhenius behaviour with similar activation energies.
KW - Amorphous
KW - Conductivity
KW - Impedance spectroscopy
KW - Lithium diffusion
KW - Lithium niobate
KW - Nanocrystalline ceramics
UR - http://www.scopus.com/inward/record.url?scp=30744478653&partnerID=8YFLogxK
U2 - 10.4028/www.scientific.net/ddf.237-240.1016
DO - 10.4028/www.scientific.net/ddf.237-240.1016
M3 - Article
AN - SCOPUS:30744478653
VL - 237-240
SP - 1016
EP - 1021
JO - Defect and Diffusion Forum
JF - Defect and Diffusion Forum
SN - 1012-0386
IS - PART 2
ER -