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Chapter
On Various Anomalies in the Temperature Derivative of Transport Properties in RE Metallic Compounds
Some renewed interest in the anomalies of transport coefficients of metallic magnets undergoing a phase transition has recently taken place. This has led to new experimental results. In the following, we exami...
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Chapter
Electrical and Thermal Properties of Magnetically Ordered Metallic Compounds TbZn, TbGd And GdCd
Simple intermetallic compounds containing rare earth metals present interesting structural and magnetic properties resulting from the interplay between various interactions mainly crystal field and exchange. S...
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Chapter
Infrared Absorption Spectrum of Ionic Powders
The infrared absorption spectrum of powders has already been discussed elsewhere, and examined along different lines of approximation. We have solved exactly Maxwell’s equations for an arbitrary distribution o...
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Chapter
Spin Reorientation Transition in Gadolinium
Accurate measurements of the temperature derivative of the electrical resistivity (dρ/dT) are used to investigate the 2nd-order spin reorientation transition in Gd at Tr = 223 K. We confirm the negligible role pl...
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Chapter
Electrothermal Instabilities at Magnetic Critical Points
Characteristic oscillations in the vicinity of magnetic ordering temperatures are explained in terms of the continuously forced ballast resistor model. Because of the highly non linear (I–V) characteristics in th...
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Chapter and Conference Paper
Transport Properties of Magnetic Metals Near Phase Transitions
The transport properties of magnetic materials near phase transitions have been the subject of rather intense research, both experimental and theoretical, even though spectacular effects are not often observed...
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Chapter and Conference Paper
Electromagnetic scattering in granular media
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Chapter
Two Phase Flow through Packed Bed Static and Dynamic Accessibilities of the Packing
We present a simple description of a gas-liquid flow through a packed bed under trickle flow conditions. A careful examination of the physics of the phenomena leads us to model the flow as a directed percolati...
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Article
Dimensionality crossover regimes due to microcrystalline anisotropy in the resistivity of granular Y1Ba2Cu3O7−y in weak magnetic fields at low temperature
Precise measurements of the electrical resitivity of Y1Ba2Cu3O7−y have been taken in the temperature range between the “percolation transition” temperatureT R and the “superco...
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Chapter
Thermodynamic Fluctuations and their Dimensionality in Ceramic Superconductors Out of Transport Properties Measurements
Information concerning the dimensionality of the thermal flustuations of the new high temperature ceramic superconductors, can be derived from the excess conductivity (paraeonductivity) near the transition tem...
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Article
High temperature crossover in paraconductivity of granular Y1Ba2Cu3O7-y
We have examined the deviation from linearity of the temperature dependence of the electrical resistivity of a YBaCuO ceramics. We have observed at high temprature a crossover behavior toward a logarithmic tem...
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Article
Theory of the thermoelectric power of model semimetals and semiconductors
We briefly discuss available theories as well as hypotheses behind numerical work for the thermoelectric power (TEP). In particular we emphasize shortcomings for comparing usual theoretical and numerical resul...
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Article
Superconductivity fluctuations in Bi(Pb) based granular ceramics superconductors: evidence for fractal behavior
We report precise measurements of the electrical resistivity in three different Bi(Pb) based granular ceramics superconductors. We show that a single critical exponent (5/6) describes the superconductivity flu...
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Chapter
Paraconductivity Measurements and Comparative Studies of Fluctuations in BiSrCaCuO, YBaCuo and YBaCuO with Gd Substitution
Information concerning the dimensionality of the superconductive fluctuations in the new high temperature superconductors can be derived from the excess conductivity (or paraconductivity) near the transition t...
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Chapter
Superconductivity Fluctuation Effects on Electrical and Thermal Transport Phenomena. H=0,T>TcI
The shape of the electrical resistance versus temperature curve in the vicinity of a superconductivity transition depends on the amount of superconducting materials (among other things) in the sample. The same...
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Article
Theory of thermoelectric power of model semimetals and semiconductors
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Chapter and Conference Paper
Competition between two kinds of entities in a Diffusion—Limited Aggregration process
An extra degree of freedom (the “spin”) is added in the well-known Diffusion-Limited Aggregation growth model. A physically relevant coupling energy between aggregating spins in presence of an external magneti...
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Article
Systems of reduced electron concentration and dimensionality
Semi-conductors, semi-metals and high critical temperature superconductors are systems with a reduced number of carriers and present effects which are sometimes related to a reduced dimensionality. We consider...
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Article
Simulated growth and microstructure of DyBa2Cu3O7−x with and without Dy2BaCuO5 addition
We present optical observations of magnetically melt-textured DyBa2Cu3O7−x with and without 20 wt. % excess of Dy2BaCuO5. From these observations, we propose some kinetic mechanism of the growth of 123 compounds....
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Article
Magnetotransport study of in situ magnetic field textured Dy1Ba2Cu3O7−δ superconductors
The electrical resistivity, thermoelectric power and the Nernst effect have been studied as a function of temperature and magnetic field for a typical superconductor DyBa2Cu3O7−δ magnetically textured in situ at ...
