Nuclear spin relaxation and atomic motion in inorganic glasses

Kanert, O.; Steinert, J.; Jain, Himanshu; Ngai, K. L.

doi:10.1016/0022-3093(91)90715-i

Cited by 46 publications

(20 citation statements)

References 28 publications

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“…A similar trend has been reported earlier in case of KSbF 4 and superionic glasses [27][28][29]. The low activation energy from NMR measurements is generally ascribed to be due to a local hop of an ion and E a (NMR) is treated as the actual microscopic activation energy of ionic diffusion [30]. However the measurement of E a (NMR) from the low temperature slope of the corresponding T 1 data shall be more appropriate [31].…”

mentioning

confidence: 56%

Temperature dependence of ¹⁹F NMR and ion transport parameters of fluoride ion conductors SnF₂—PbF₂ and 2SnF₂—NH₄F prepared by mechanical milling

Kumar¹,

Yamada²,

Okuda³

et al. 2003

Physica Status Solidi (b)

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Abstract19F NMR studies have been carried out on mixed metal fluorides composed of SnF2—PbF2 and 2SnF2—NH4F and prepared by mechanical milling. Motional narrowing observed in the variation of 19F NMR linewidth as a function of temperature for both the systems suggests the occurrence of F− ion diffusion. The variation of different ion transport parameters calculated from NMR results like jump frequency, diffusion coefficient, and conductivity with temperature has been found to be closely related with experimentally measured conductivity results.

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mentioning

confidence: 56%

Temperature dependence of ¹⁹F NMR and ion transport parameters of fluoride ion conductors SnF₂—PbF₂ and 2SnF₂—NH₄F prepared by mechanical milling

Kumar¹,

Yamada²,

Okuda³

et al. 2003

Physica Status Solidi (b)

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“…The relationship between parameters from NMR and conductivity spectroscopy in disordered media, such as glasses, has been discussed in detail by Ngai and coworkers. [49][50][51][52][53][54] Careful inspection of Fig. 7(a) shows that the sample milled for 100 h shows even lower conductivities as compared to that milled for 10 h. We also see a slight increase of the corresponding activation energy E a (0.64 eV vs. 0.61 eV).…”

Section: F Nmr Spin-lock Nmr and The Effect Of Long-term Millingmentioning

confidence: 81%

Mismatch in cation size causes rapid anion dynamics in solid electrolytes: the role of the Arrhenius pre-factor

Breuer

Wilkening

2018

Dalton Trans.

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Crystalline ion conductors exhibiting fast ion dynamics are of utmost importance for the development of, e.g., sensors or rechargeable batteries. In some layer-structured or nanostructured compounds fluorine ions participate in remarkably fast self-diffusion processes. As has been shown earlier, F ion dynamics in nanocrystalline, defect-rich BaF 2 is much higher than that in the coarse-grained counterpart BaF 2 . The thermally metastable fluoride (Ba,Ca)F 2 , which can be prepared by joint high-energy ball milling of the binary fluorides, exhibits even better ion transport properties. While long-range ion dynamics has been studied recently, less information is known about local ion hopping processes to which 19 F nuclear magnetic resonance (NMR) spin-lattice relaxation is sensitive. The present paper aims at understanding ion dynamics in metastable, nanocrystalline (Ba,Ca)F 2 by correlating short-range ion hopping with long-range transport properties. Variable-temperature NMR line shapes clearly indicate fast and slow F spin reservoirs. Surprisingly, from an atomic-scale point of view increased ion dynamics at intermediate values of compo-sition is reflected by increased absolute spin-lattice relaxation rates rather than by a distinct minimum in activation energy. Hence, the pre-factor of the underlying Arrhenius relation, which is determined by the number of mobile spins, the attempt frequency and entropy effects, is identified as the parameter that directly enhances short-range ion dynamics in metastable (Ba,Ca)F 2 . Concerted ion migration could also play an important role to explain the anomalies seen in NMR spin-lattice relaxation.

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“…Small activation energies have been interpreted in terms of localized hopping in a nonperiodic potential 20 arising from disordered distribution of ions. A model has been proposed for inorganic glasses, 21 which explains the low temperature (TϽ200 K͒ behavior of the nuclear spin relaxation in terms of thermally activated low-frequency excitations of disordered modes. The modes are described by asymmetric double-well potential configurations ͑ADWP͒ with suitable densities of states.…”

Section: ͑8͒mentioning

confidence: 99%

Correlated ion hopping in single-crystal yttria-stabilized zirconia

León¹,

Lucı́a²,

Santamarı́a³

1997

Phys. Rev. B

195

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A study of the effect of correlated ion motion on the electrical conductivity relaxation in single-crystalline yttria-stabilized zirconia is presented. Complex admittance in the radio frequency range show power-law dependencies in the real part of the conductivity at high frequencies of the form n and asymmetric electric modulus plots as a result of correlations. An analysis of the frequency dependence of the electric modulus is conducted to obtain time decay functions of the form exp͓Ϫ(t/ ) ␤ ͔ from an analytical distribution of relaxation times. Correlation times, and parameters n and ␤ characterizing the relaxation in time and frequency domains are compared to show the equivalence of time and frequency representations. The common origin of ac and dc processes is discussed in view of the frequency dependence of the complex conductivity. From a macroscopic activation energy for ion motion Eϭ1.16 eV and a ␤ value of 0.43, a single-ion microscopic activation energy E a ϭ0.5 eV is obtained as ␤E according to Ngai's coupling model. The microscopic activation energy is related to the association energy of oxygen vacancies.

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Nuclear spin relaxation and atomic motion in inorganic glasses

Cited by 46 publications

References 28 publications

Temperature dependence of ¹⁹F NMR and ion transport parameters of fluoride ion conductors SnF₂—PbF₂ and 2SnF₂—NH₄F prepared by mechanical milling

Temperature dependence of ¹⁹F NMR and ion transport parameters of fluoride ion conductors SnF₂—PbF₂ and 2SnF₂—NH₄F prepared by mechanical milling

Mismatch in cation size causes rapid anion dynamics in solid electrolytes: the role of the Arrhenius pre-factor

Correlated ion hopping in single-crystal yttria-stabilized zirconia

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Nuclear spin relaxation and atomic motion in inorganic glasses

Cited by 46 publications

References 28 publications

Temperature dependence of 19F NMR and ion transport parameters of fluoride ion conductors SnF2—PbF2 and 2SnF2—NH4F prepared by mechanical milling

Temperature dependence of 19F NMR and ion transport parameters of fluoride ion conductors SnF2—PbF2 and 2SnF2—NH4F prepared by mechanical milling

Mismatch in cation size causes rapid anion dynamics in solid electrolytes: the role of the Arrhenius pre-factor

Correlated ion hopping in single-crystal yttria-stabilized zirconia

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Temperature dependence of ¹⁹F NMR and ion transport parameters of fluoride ion conductors SnF₂—PbF₂ and 2SnF₂—NH₄F prepared by mechanical milling

Temperature dependence of ¹⁹F NMR and ion transport parameters of fluoride ion conductors SnF₂—PbF₂ and 2SnF₂—NH₄F prepared by mechanical milling