Analysis of the ionic contribution to the electrical conductivity of LiNbO3 crystals

The dielectric and impedance spectra of TlGaSe2 crystals have been studied at temperatures in the 100–500 K range in the alternating current (AC [Formula: see text]1 V). It has been shown that the conductivity of TlGaSe2 crystals is mainly an ionic characteristic at temperatures above 400 K. The well-defined peak at the frequency dependence of the imaginary part of impedance [Formula: see text] is observed in the 215–500 K temperature range. In a constant field, there occurs a significant decrease in electrical conductivity [Formula: see text] in due course. The ionic contribution to conductivity (76% at [Formula: see text]) has been estimated from a kinetic change in electrical conductivity [Formula: see text] under the influence of a constant electric field. The diagram analysis in a complex plane [Formula: see text] has been conducted by applying the method of an equivalent circuit of the substation. It has been determined that the average relaxation time of the electric module of the sample is [Formula: see text].

Download Full-text

Phenomenology of the Temperature-Frequency Dispersion of Electrical Properties of Aluminium-Substituted Lithium-Iron Spinel

Фізика і хімія твердого тіла ◽

10.15330/pcss.20.4.423-431 ◽

2019 ◽

Vol 20 (4) ◽

pp. 423-431

Author(s):

I.M. Gasiuk ◽

D.M. Chervinko ◽

M.I. Gasiuk ◽

L.Ya. Lozinska

Keyword(s):

Activation Energy ◽

Electrical Conductivity ◽

Electrical Properties ◽

Frequency Dispersion ◽

Phenomenological Approach ◽

Total Conductivity ◽

Electronic Contribution ◽

Ionic Contribution

The conductivity of the Li-containing Al-oxoferrite samples has been studied. Using Jonsher’s phenomenological approach, existence of 2 types of conductivity (electronic and ionic) in the above mentioned samples has been confirmed. Using Cole-Cole method, the character of electrical conductivity dispersion of the samples has been shown. The activation energy for the series of samples have been calculated. It has been found that the ionic contribution to the total conductivity of the system is much lower that the corresponding electronic contribution.

Download Full-text

Removing Substrate Background in TEM Microanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052857 ◽

1974 ◽

Vol 32 ◽

pp. 568-569

Author(s):

John C. Russ ◽

Nicholas C. Barbi

Keyword(s):

Electrical Conductivity ◽

Rapid Growth ◽

Organic Film ◽

Absolute Concentration ◽

Background Signal ◽

X Ray ◽

Elemental Concentrations ◽

Transmission Electron ◽

Electron Microscopes ◽

The Continuum

The rapid growth of interest in attaching energy-dispersive x-ray analysis systems to transmission electron microscopes has centered largely on microanalysis of biological specimens. These are frequently either embedded in plastic or supported by an organic film, which is of great importance as regards stability under the beam since it provides thermal and electrical conductivity from the specimen to the grid.Unfortunately, the supporting medium also produces continuum x-radiation or Bremsstrahlung, which is added to the x-ray spectrum from the sample. It is not difficult to separate the characteristic peaks from the elements in the specimen from the total continuum background, but sometimes it is also necessary to separate the continuum due to the sample from that due to the support. For instance, it is possible to compute relative elemental concentrations in the sample, without standards, based on the relative net characteristic elemental intensities without regard to background; but to calculate absolute concentration, it is necessary to use the background signal itself as a measure of the total excited specimen mass.

Download Full-text

Macromolecular structures of biological specimens are not obscured by controlled osmium impregnation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100076639 ◽

1983 ◽

Vol 41 ◽

pp. 606-607

Author(s):

Klaus-Ruediger Peters ◽

Samuel A. Green

Keyword(s):

Thin Films ◽

Electrical Conductivity ◽

Critical Point ◽

Metal Films ◽

High Magnification ◽

Osmium Impregnation ◽

Instrumental Resolution ◽

20 Nm ◽

Continuous Metal

High magnification imaging of macromolecules on metal coated biological specimens is limited only by wet preparation procedures since recently obtained instrumental resolution allows visualization of topographic structures as smal l as 1-2 nm. Details of such dimensions may be visualized if continuous metal films with a thickness of 2 nm or less are applied. Such thin films give sufficient contrast in TEM as well as in SEM (SE-I image mode). The requisite increase in electrical conductivity for SEM of biological specimens is achieved through the use of ligand mediated wet osmiuum impregnation of the specimen before critical point (CP) drying. A commonly used ligand is thiocarbohvdrazide (TCH), first introduced to TEM for en block staining of lipids and glvcomacromolecules with osmium black. Now TCH is also used for SEM. However, after ligand mediated osinification nonspecific osmium black precipitates were often found obscuring surface details with large diffuse aggregates or with dense particular deposits, 2-20 nm in size. Thus, only low magnification work was considered possible after TCH appl ication.

Download Full-text

Total Body Electrical Conductivity Measurements in the Neonate

Clinics in Perinatology ◽

10.1016/s0095-5108(18)30515-3 ◽

1991 ◽

Vol 18 (3) ◽

pp. 611-627 ◽

Cited By ~ 15

Author(s):

Marta L. Fiorotto ◽

William J. Klish

Keyword(s):

Electrical Conductivity ◽

Conductivity Measurements ◽

Total Body

Download Full-text

Electrical Conductivity Imparted to Liquid Air by Alpha Rays

Scientific American ◽

10.1038/scientificamerican03201915-191bsupp ◽

1915 ◽

Vol 79 (2046supp) ◽

pp. 191-191

Keyword(s):

Electrical Conductivity

Download Full-text

Effect of MCl (M = Na, K) addition on microstructure and electrical conductivity of forsterite

The European Physical Journal Applied Physics ◽

10.1051/epjap/2020200161 ◽

2020 ◽

Vol 92 (1) ◽

pp. 10901

Author(s):

Saloua El Asri ◽

Hamid Ahamdane ◽

Lahoucine Hajji ◽

Mohamed El Hadri ◽

Moulay Ahmed El Idrissi Raghni ◽

...

Keyword(s):

Heat Treatment ◽

Electrical Conductivity ◽

Single Phase ◽

Sol Gel ◽

Complex Impedance ◽

Transmission Spectra ◽

Electrical Measurements ◽

Cation Type ◽

Edx Analyses ◽

The Fourier Transform

Forsterite single phase powder Mg2SiO4 was synthesized by sol–gel method alongside with heat treatment, using two different cation alkaline salts MCl as mineralizers (M = Na, K) with various mass percentages (2.5, 5, 7.5, and 10 wt.%). In this work, we report on the effect of the cation type and the added amount of used mineralizer on microstructure and electrical conductivity of Mg2SiO4. The formation of forsterite started at 680–740 °C and at 630–700 °C with KCl and NaCl respectively, as shown by TG-DTA and confirmed by XRD. Furthermore, the Fourier transform infrared (FTIR) transmission spectra indicated bands corresponding to vibrations of forsterite structure. The morphology and elemental composition of sintered ceramics were examined by SEM-EDX analyses, while their densities, which were measured by Archimedes method, increased with addition of both alkaline salts. The electrical measurements were performed by Complex Impedance Spectroscopy. The results showed that electrical conductivity increased with the addition of both mineralizers, which was higher for samples prepared with NaCl than those prepared with KCl.

Download Full-text