Anomaly electrical conductivity

Fe(qsal)2][Ni(dmit)2]3.CH3CN.H20 exhibits a room temperature conductivity of 2.0 S cm-1 and behaves as a semiconductor between 300 and 70 K (Fig. 12). It also exhibits a broad spin transition between 300 and 60 K (Fig. 13). Anomalies are observed in the range 120-90 K, both in the magnetic and electric measurements, clearly indicating a synergy between the SCO phenomenon and the electrical conduction. 

In 1974, the electrical conductivity of LajCuC was re-determined (130) on a powdered sample prepared at 900-950°C. A 4-probe d.c. cell was used and the electrical data obtained between 100 and 900°C indicated this material to be a metallic conductor. A slight anomaly in the conductivity was noted at 310°C. 

Perhaps a more decisive discrimination between Ising and mean-field behavior could be provided by the investigation of weak anomalies [6] as predicted for the specific heat. Such weak anomalies are absent in the mean-field case (cf. Table I). Except for the diameter anomalies already mentioned, no thermodynamic investigations of weak anomalies were reported so far. However, dynamical properties such as the shear viscosity and electrical conductance may show weak anomalies as well. 

Electrical conductivity depends on several factors, such as temperature, pressure, and moisture content of the coal. The electrical conductivity of coal is quite pronounced at high temperatures [especially above 600°C (1112°F)], where coal structure begins to break down. Moisture affects electrical conductivity to a marked extent, resulting in a greatly increased conductivity. To prevent any anomalies from the conductance due to water, the coal is usually maintained in a dry, oxygen-free atmosphere, and to minimize the problems that can arise, particularly because of the presence of water, initial measurements are usually taken at approximately 200°C (392°F) and then continued to lower temperatures. 

At high concentrations (mixtures with a low water content) Sapozhnikov found certain anomalies in the vapour pressure of HN03 and in its electric conductivity. He ascribed them to the formation of nitric anhydride N205. Thus the equation will be ... 

Another property related to a is the electrical conductance, which diverges as rl a. Bonetti and Oleinikova [113] proved the existence of an Ising-type (1 — a) anomaly for some picrate systems, finding no essential difference between Coulomb and solvophobic systems. Finally, the viscosity of Ising-like... 

The anomalies in electrical conductivity observed for nanocrystalline specimens can be explained by a model in which a defect pair formation was proposed [13, 14, 30]. The association between oxygen vacancies and acceptor dopants has been considered, which results in the formation of a... 

George and Karkhanavala 208) have ascribed a value of about 450 C for the transition point in a-UjOg from the break occurring in the electrical conductivity vs. reciprocal temperature curve. Girdhar and Westrum 288) have found a small A-type anomaly of specific heat capacity in UjOg at 210"C. 

Yamamura H, Nishino H, Kakinuma K, Nomura K (2003) Electrical conductivity anomaly around fluorite-pyrochlore phase boundary. Solid State Ionics 158 359-365... 

The phase transition described above can be characterized as a second order transition. However, the nature of the metal-insulator-transition in FA2X-salts is still an unsolved question a a matter of continuing research. In DSC experiments two transitions at approximately 200 K an 180 K are observed of which the first one is the transition which can be monitored crystallographically. However, the electronic properties change abruptly at 180 K. The assumptic of the existence of a lower transition is also supported by some results of ESR- and NMR-experiments with a pronuonced line broadening at and below the phase transition around K as well as by measurements of the static susceptibility Wd the electrical conductivity. At thi temperature no anomalies in the temperature dependence of the crystal structures can be detected... 

The Fermi surface topology of cubic nitrides was first studied by Em and Switendick (1965) for TiN. Fig. 3.9 shows the cross-sections of the first three sheets of the TiN Fermi surface. Later, the Fermi surface was calculated by the KKR method and compared with the experimental data by Schadler, Weinberger, Klima and Neckel (1984), but no essential difference from the results by Ern and Switendick was found. Fig. 3.9 shows that the electrical conductivity of TiN is electronic in nature. This is evident from the position of the Fermi energy inside the metal states band. Other calculations of Fermi surfaces have been carried out by Fong and Cohen (1972) for NbN and by Ivashchenko (1984) for ZrN. The latter work also studied the relation between the Fermi surface topology and the phonon spectra. It is known that for longitudinal acoustic phonons there may be a decrease in frequency for the wave vectors q, at which the generalised susceptiblity x(q) reveals maxima. This situation may take place if the Fermi surface has lane-parallel parts. It has been shown that this is true for ZrN, and it may explain the appearance of phonon anomalies in ZrN. The presence of x(q) maxima also leads to an increase... 

Electrical conductivity anomaly in near-stoichiometric plutonium dioxide. Journal of Nuclear Materials, Vol.95, pp.181-184... 

Eddy-current methods are used to measure a variety of material characteristics and conditions. They are applied in the flaw detection mode for the detection of surface-connected or near-surface anomalies. The test objects must be electrically conductive and be capable of uniform contact by an eddy-current probe. Special equipment and specialized probes are required to perform the inspection. Procedure development, calibration artifacts, and process control are required to assure reproducibility of response in the selected test object. 

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