Uncommon nuclear-spin relaxation in fluorozirconate glasses at low temperatures

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

doi:10.1103/physrevb.43.7481

Cited by 50 publications

(17 citation statements)

References 21 publications

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“…A quadratic trend, as the one experimentally observed here, is obtained for p(∆E) ∝ ∆E. Notably, the same result was derived also taking into account the thermally activated dynamics in asymmetric double wells characterizing the glasses [36,37] and a recent implementation of the same approach could explain also the quadratic T dependence of 1/T 1e observed at low T in various amorphous materials, including organic glasses [38].…”

Section: K (supporting

confidence: 83%

The role of the glassy dynamics and thermal mixing in the dynamic nuclear polarization and relaxation mechanisms of pyruvic acid

Filibian

Serra

Moscardini

et al. 2014

Phys. Chem. Chem. Phys.

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The temperature dependence of 1 H and 13 C nuclear spin-lattice relaxation rate 1/T1 has been studied in the 1.6 K -4.2 K temperature range in pure pyruvic acid and in pyruvic acid containing trityl radicals at a concentration of 15 mM. The temperature dependence of 1/T1 is found to follow a quadratic power law for both nuclei in the two samples. Remarkably the same temperature dependence is displayed also by the electron spin-lattice relaxation rate 1/T1e in the sample containing radicals. These results are explained by considering the effect of the structural dynamics on the relaxation rates in pyruvic acid. Dynamic nuclear polarization experiments show that below 4 K the 13 C build up rate scales with 1/T1e, in analogy to 13 C 1/T1 and consistently with a thermal mixing scenario where all the electrons are collectively involved in the dynamic nuclear polarization process and the nuclear spin reservoir is in good thermal contact with the electron spin system.

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Section: K (supporting

confidence: 83%

The role of the glassy dynamics and thermal mixing in the dynamic nuclear polarization and relaxation mechanisms of pyruvic acid

Filibian

Serra

Moscardini

et al. 2014

Phys. Chem. Chem. Phys.

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“…This phenomenon has been referred as the “nearly constant loss” (NCL) behavior1718. The NCL is generally regarded as resulting from relaxations of the charges moving in the asymmetric double-well potentials19. Such relaxation involves highly localized motions rather than the dominating hopping processes which usually occur in the ferrites at high temperatures121316202122.…”

Section: Resultsmentioning

confidence: 99%

Dielectric relaxation, resonance and scaling behaviors in Sr3Co2Fe24O41 hexaferrite

Tang

Jiang

Qian

et al. 2015

Sci Rep

203

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The dielectric properties of Z-type hexaferrite Sr3Co2Fe24O41 (SCFO) have been investigated as a function of temperature from 153 to 503 K between 1 and 2 GHz. The dielectric responses of SCFO are found to be frequency dependent and thermally activated. The relaxation-type dielectric behavior is observed to be dominating in the low frequency region and resonance-type dielectric behavior is found to be dominating above 108 Hz. This frequency dependence of dielectric behavior is explained by the damped harmonic oscillator model with temperature dependent coefficients. The imaginary part of impedance (Z″) and modulus (M″) spectra show that there is a distribution of relaxation times. The scaling behaviors of Z″ and M″ spectra further suggest that the distribution of relaxation times is temperature independent at low frequencies. The dielectric loss spectra at different temperatures have not shown a scaling behavior above 108 Hz. A comparison between the Z″ and the M″ spectra indicates that the short-range charges motion dominates at low temperatures and the long-range charges motion dominates at high temperatures. The above results indicate that the dielectric dispersion mechanism in SCFO is temperature independent at low frequencies and temperature dependent at high frequencies due to the domination of resonance behavior.

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“…3͒, is the most interesting result of this work. 26 Real experimental evidence of ADWP has been seen in some ionic glasses, however the well-defined ones show up as peaks in the dielectric loss and not as the NCL. For example, these properties suggest that structural disorder is not a prerequisite requirement for the mechanism that generates the NCL.…”

Section: Discussionmentioning

confidence: 99%

Near constant loss in glassy and crystalline LiAlSi2O6 from conductivity relaxation measurements

Rizos

Alifragis

Ngai

et al. 2001

The Journal of Chemical Physics

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Articles you may be interested inEffect of pressure on decoupling of ionic conductivity from structural relaxation in hydrated protic ionic liquid, lidocaine HClEffects of ions on the dielectric permittivity and relaxation rate and the decoupling of ionic diffusion from dielectric relaxation in supercooled liquid and glassy 1-propanol Polycrystalline and glassy LiAlSi 2 O 6 are studied by dielectric relaxation measurements for the purpose of characterizing the nearly frequency independent contribution to the dielectric loss ͑near constant loss͒, which is commonly found in glassy ionic conductors independent of the chemical and physical structures. The data show the near constant loss is present in both the polycrystalline and glassy states of LiAlSi 2 O 6 . Further, its magnitude and temperature dependence is comparable in both forms of the same substance. The implications of these findings on the mechanism that gives rise to the near constant loss are discussed.

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Uncommon nuclear-spin relaxation in fluorozirconate glasses at low temperatures

Cited by 50 publications

References 21 publications

The role of the glassy dynamics and thermal mixing in the dynamic nuclear polarization and relaxation mechanisms of pyruvic acid

The role of the glassy dynamics and thermal mixing in the dynamic nuclear polarization and relaxation mechanisms of pyruvic acid

Dielectric relaxation, resonance and scaling behaviors in Sr3Co2Fe24O41 hexaferrite

Near constant loss in glassy and crystalline LiAlSi2O6 from conductivity relaxation measurements

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