Details
| Original language | English |
|---|---|
| Pages (from-to) | 7303-7306 |
| Number of pages | 4 |
| Journal | Journal of Physical Chemistry B |
| Volume | 102 |
| Issue number | 38 |
| Publication status | Published - 17 Sept 1998 |
Abstract
Nanocrystalline (n) LiNbO3 was prepared by high-energy ball milling from the polycrystalline (p) material. Grain sizes were determined by XRD measurements and TEM images; thermal stability ranges of the samples were examined by DTA. NMR investigations of the diffusion-induced 7Li spin-lattice relaxation (SLR) rate T1-1 of n-LiNbO3 in the temperature range from T = 140 to 460 K at frequencies between ν = 24 and 78 MHz revealed a reduced activation energy on the low-temperature side of the typical peak in a log T1-1 vs T-1 plot in comparison with results obtained from experiments performed on the p-material between 300 and 1400 K. Corresponding measurements of the SLR rate in the rotating reference frame yielded an asymmetric peak in the case of p-LiNbO3, in contradiction to standard BPP theory, whereas in H-LiNbO3 only a weakly temperature-dependent relaxation rate background was observed. Furthermore, neither in n-nor in p-LiNbO3 BPP-type frequency dependencies of the SLR rate, i.e., T1-1 ∝ ν-β with β = 2, were found. The determined values ranging from β = 1.1 to 1.5 are ascribed to the influence of structural disorder and Coulomb interaction on the diffusive motion.
ASJC Scopus subject areas
- Chemistry(all)
- Physical and Theoretical Chemistry
- Materials Science(all)
- Surfaces, Coatings and Films
- Materials Science(all)
- Materials Chemistry
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In: Journal of Physical Chemistry B, Vol. 102, No. 38, 17.09.1998, p. 7303-7306.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - NMR relaxation study of ion dynamics in nanocrystalline and polycrystalline LiNbO3
AU - Bork, D.
AU - Heitjans, P.
PY - 1998/9/17
Y1 - 1998/9/17
N2 - Nanocrystalline (n) LiNbO3 was prepared by high-energy ball milling from the polycrystalline (p) material. Grain sizes were determined by XRD measurements and TEM images; thermal stability ranges of the samples were examined by DTA. NMR investigations of the diffusion-induced 7Li spin-lattice relaxation (SLR) rate T1-1 of n-LiNbO3 in the temperature range from T = 140 to 460 K at frequencies between ν = 24 and 78 MHz revealed a reduced activation energy on the low-temperature side of the typical peak in a log T1-1 vs T-1 plot in comparison with results obtained from experiments performed on the p-material between 300 and 1400 K. Corresponding measurements of the SLR rate in the rotating reference frame yielded an asymmetric peak in the case of p-LiNbO3, in contradiction to standard BPP theory, whereas in H-LiNbO3 only a weakly temperature-dependent relaxation rate background was observed. Furthermore, neither in n-nor in p-LiNbO3 BPP-type frequency dependencies of the SLR rate, i.e., T1-1 ∝ ν-β with β = 2, were found. The determined values ranging from β = 1.1 to 1.5 are ascribed to the influence of structural disorder and Coulomb interaction on the diffusive motion.
AB - Nanocrystalline (n) LiNbO3 was prepared by high-energy ball milling from the polycrystalline (p) material. Grain sizes were determined by XRD measurements and TEM images; thermal stability ranges of the samples were examined by DTA. NMR investigations of the diffusion-induced 7Li spin-lattice relaxation (SLR) rate T1-1 of n-LiNbO3 in the temperature range from T = 140 to 460 K at frequencies between ν = 24 and 78 MHz revealed a reduced activation energy on the low-temperature side of the typical peak in a log T1-1 vs T-1 plot in comparison with results obtained from experiments performed on the p-material between 300 and 1400 K. Corresponding measurements of the SLR rate in the rotating reference frame yielded an asymmetric peak in the case of p-LiNbO3, in contradiction to standard BPP theory, whereas in H-LiNbO3 only a weakly temperature-dependent relaxation rate background was observed. Furthermore, neither in n-nor in p-LiNbO3 BPP-type frequency dependencies of the SLR rate, i.e., T1-1 ∝ ν-β with β = 2, were found. The determined values ranging from β = 1.1 to 1.5 are ascribed to the influence of structural disorder and Coulomb interaction on the diffusive motion.
UR - http://www.scopus.com/inward/record.url?scp=0000054083&partnerID=8YFLogxK
U2 - 10.1021/jp981536y
DO - 10.1021/jp981536y
M3 - Article
AN - SCOPUS:0000054083
VL - 102
SP - 7303
EP - 7306
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
SN - 1520-6106
IS - 38
ER -