Magnetic Aftereffect Due to Hydrogen in NdCo5

1973 ◽  
Vol 51 (23) ◽  
pp. 2407-2414 ◽  
Author(s):  
I. Maartense
Keyword(s):  
Single Crystals ◽  
Relaxation Times ◽  
Low Frequency ◽  
Unknown Origin ◽  
Arrhenius Relation ◽  
Magnetic Aftereffect

In single crystals of NdCo5 containing small amounts of hydrogen, a.c. susceptibility measurements reveal disaccommodation effects and low frequency loss peaks between 130 and 220 °K. Relaxation times, measured over ~5 decades, fit an Arrhenius relation of the form τ = τ0 exp (E/kT), with E = 0.40 ± 0.02 eV and τ0 = 10−12.3 ± 0.4 s. Hydrogen can be introduced by exposing the sample to the gas, or by etching it in acids; it can be removed by heating in a vacuum at ~750 °K. In the degassed material, additional relaxations, of unknown origin, are found near 375 and 720 °K, with E = 0.7 ± 0.1 and 1.6 ± 0.3 eV respectively. The possible importance of these effects to the coercivity of RCo5 compounds is pointed out.

Dielectric Relaxation Studies of Silver Nanoparticles dispersed Liquid Crystal

2015 ◽  
Vol 8 (3) ◽  
pp. 2176-2188 ◽  
Author(s):  
Keisham Nanao Singh
Keyword(s):  
Activation Energy ◽  
Silver Nanoparticles ◽  
Liquid Crystal ◽  
Dielectric Relaxation ◽  
Relaxation Process ◽  
Relaxation Times ◽  
Low Frequency ◽  
Bulk Liquid ◽  
Molecular Rearrangement ◽  
Relaxation Studies

This article reports on the Dielectric Relaxation Studies of two Liquid Crystalline compounds - 7O.4 and 7O.6 - doped with dodecanethiol capped Silver Nanoparticles. The liquid crystal molecules are aligned homeotropically using CTAB. The low frequency relaxation process occurring above 1 MHz is fitted to Cole-Cole formula using the software Dielectric Spectra fit. The effect of the Silver Nanoparticles on the molecular dipole dynamics are discussed in terms of the fitted relaxation times, Cole-Cole distribution parameter and activation energy. The study indicate a local molecular rearrangement of the liquid crystal molecules without affecting the order of the bulk liquid crystal molecules but these local molecules surrounding the Silver Nanoparticles do not contribute to the relaxation process in the studied frequency range. The observed effect on activation energy suggests a change in interaction between the nanoparticles/liquid crystal molecules.

Low-Frequency Central Peaks In Relaxor Ferroelectric PZN-9%PT Single Crystals

2007 ◽  
Vol 347 (1) ◽  
pp. 25-29 ◽  
Author(s):  
Jae-Hyeon Ko ◽  
Do Han Kim ◽  
Seiji Kojima
Keyword(s):  
Single Crystals ◽  
Low Frequency ◽  
Relaxor Ferroelectric

scholarly journals Determination of the Distribution of Relaxation Times by Means of Pulse Evaluation for Offline and Online Diagnosis of Lithium-Ion Batteries

Batteries ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 36
Author(s):  
Erik Goldammer ◽  
Julia Kowal
Keyword(s):  
Lithium Ion Batteries ◽  
Electrochemical Impedance ◽  
Sampling Rate ◽  
Relaxation Times ◽  
Low Frequency ◽  
Lithium Ion ◽  
Battery Management ◽  
Time Constants ◽  
Time Domain Data ◽  
Aging Study

The distribution of relaxation times (DRT) analysis of impedance spectra is a proven method to determine the number of occurring polarization processes in lithium-ion batteries (LIBs), their polarization contributions and characteristic time constants. Direct measurement of a spectrum by means of electrochemical impedance spectroscopy (EIS), however, suffers from a high expenditure of time for low-frequency impedances and a lack of general availability in most online applications. In this study, a method is presented to derive the DRT by evaluating the relaxation voltage after a current pulse. The method was experimentally validated using both EIS and the proposed pulse evaluation to determine the DRT of automotive pouch-cells and an aging study was carried out. The DRT derived from time domain data provided improved resolution of processes with large time constants and therefore enabled changes in low-frequency impedance and the correlated degradation mechanisms to be identified. One of the polarization contributions identified could be determined as an indicator for the potential risk of plating. The novel, general approach for batteries was tested with a sampling rate of 10 Hz and only requires relaxation periods. Therefore, the method is applicable in battery management systems and contributes to improving the reliability and safety of LIBs.

Low frequency Raman spectra of the liquid and plastic crystal phases of O2, N2, CO, and of Ar crystals with these molecules as guests

1982 ◽  
Vol 60 (9) ◽  
pp. 1358-1364 ◽  
Author(s):  
N. H. Rich ◽  
M. J. Clouter ◽  
H. Kiefte ◽  
S. F. Ahmad
Keyword(s):  
Single Crystals ◽  
Raman Spectra ◽  
Phonon Mode ◽  
Low Frequency ◽  
Impurity Molecule ◽  
Spectral Features ◽  
Background Impurity ◽  
Crystal Phases ◽  
Distinct Features ◽  
Frequency Feature

Low frequency Raman spectra of single crystals of orientationally disordered phases of oxygen, nitrogen, and carbon monoxide, and spectra of those substances as liquids show two linear segments in semi-log plots. Slopes of the higher frequency segments are nearly equal for all cases; slopes of the lower frequency segments are particular to the substance and are nearly the same in both liquid and crystal for O2 and CO. Spectra of single crystals of argon doped with O2, N2, or CO show two distinct features superimposed on a sloping background. Impurity molecule reorientation apparently accounts satisfactorily for all spectral features, but translation–rotation coupling may allow a contribution to the higher frequency feature arising from a local phonon mode in argon.

The Spectrum of the Magnetic Aftereffect in Neutron‐Irradiated Ni Single Crystals

1967 ◽  
Vol 38 (3) ◽  
pp. 1312-1313 ◽  
Author(s):  
A. Seeger ◽  
F. Walz ◽  
H. Kronmüller
Keyword(s):  
Single Crystals ◽  
Magnetic Aftereffect

Effects of director rotation relaxation on viscoelastic wave dispersion in nematic elastomer beams

2018 ◽  
Vol 24 (4) ◽  
pp. 1103-1115 ◽  
Author(s):  
Dong Zhao ◽  
Ying Liu
Keyword(s):  
Wave Motion ◽  
Relaxation Times ◽  
Low Frequency ◽  
Wave Dispersion ◽  
Frequency Limit ◽  
Anisotropic Parameter ◽  
Acoustic Design ◽  
Phase Velocities ◽  
Nematic Elastomer ◽  
Viscoelastic Wave

In this paper, the transverse wave dispersion in a nematic elastomer (NE) Timoshenko beam is studied by considering anisotropy and viscoelasticity of NEs in the low frequency limit. Firstly, the characteristic equations of wave motion in an NE beam are derived, and then numerically solved to obtain the corresponding phase velocities and attenuation factors. The influences of anisotropic parameter, director rotation and rubber relaxation times on the wave dispersion in an NE beam are discussed. Results show that unlike the situation in general isotropic viscoelastic beam, non-classical viscoelastic wave dispersion is found in NE beams. Geometric dispersion is restrained with the vanishing of cut-off frequencies for shear waves due to director rotation relaxation of NEs. This unique property promises prospective applications of NE beams in optic or acoustic design.

Effect of Purity on Dislocation-Induced Relaxations in Molybdenum Single Crystals

2015 ◽  
Vol 363 ◽  
pp. 106-111
Author(s):  
Shigeru Suzuki ◽  
Alfred Seeger
Keyword(s):  
Internal Friction ◽  
Single Crystals ◽  
High Purity ◽  
Low Frequency ◽  
Activation Process ◽  
Dislocation Interaction ◽  
Dissolved Carbon ◽  
Dislocation Pinning ◽  
Friction Measurements ◽  
Substitutional Impurities

Dislocation-induced relaxations in different molybdenum single crystals were investigated by means of low-frequency internal friction measurements in the temperature range of 20–600 K. The results indicated that the appearance of the dislocation-induced relaxations strongly depends on the purity of the molybdenum, although the intrinsic dislocation relaxations appeared at about 100 K and 450 K in the high-purity molybdenum. The molybdenum containing a small amount of carbon did not exhibit the intrinsic dislocation relaxations but rather revealed a modulus increase due to the dislocation pinning caused by the dissolved carbon. When the molybdenum containing a small amount of carbon was annealed up to 700 K, a new relaxation peak appeared at about 450 K. The activation process for this relaxation indicated that it could be attributed to the relaxation due to a carbon-dislocation interaction. In addition, it was shown that the dislocation-induced relaxations in medium-purity molybdenum were small, which was attributed to the residual substitutional impurities in the molybdenum.

Time Domain Zero Field NMR and NQR

1986 ◽  
Vol 41 (1-2) ◽  
pp. 440-444 ◽  
Author(s):  
A. Bielecki ◽  
D. B. Zax ◽  
A. M. Thayer ◽  
J. M. Millar ◽  
A. Pines
Keyword(s):  
Time Domain ◽  
Relaxation Times ◽  
Low Frequency ◽  
High Sensitivity ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Zero Field ◽  
Spin Lattice ◽  
Field Cycling ◽  
The Time Domain

Field cycling methods are described for the time domain measurement of nuclear quadrupolar and dipolar spectra in zero applied field. Since these techniques do not involve irradiation in zero field, they offer significant advantages in terms of resolution, sensitivity at low frequency, and the accessible range of spin lattice relaxation times. Sample data are shown which illustrate the high sensitivity and resolution attainable. Comparison is made to other field cycling methods, and an outline of basic instrumental requirements is given.

Low frequency internal friction in zinc single crystals

1962 ◽  
Vol 10 (4) ◽  
pp. 430-441 ◽  
Author(s):  
J.M Roberts ◽  
N Brown
Keyword(s):  
Internal Friction ◽  
Single Crystals ◽  
Low Frequency
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