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Measurements of the complex dielectric constant (ε′ + iε″) on a series on NbC-KCl composites in a wide range of concentrations are performed as a function of φ (the volume fraction of the 1–3 μm NbC grains) at frequencies of 102, 103, 104 and 105 Hz. Frequency scaling of ε = ε′ +...
Persistent link: https://www.econbiz.de/10011057022
Measurements of χ′ and χ″ have been made at 36.7 Hz, using two dual phase lock-in amplifiers, on a series of NbC-KCl composites. The measurements are made, between 4.5 and 12 K, as a function of φ (the volume fraction of the 1–3 μm NbC grains) between 0.0 and 0.40, and in AC fields...
Persistent link: https://www.econbiz.de/10011057905
Resistivity ϱxx and Hall resistivity ϱxy were measured as functions of the magnetic field, temperature, and the metal volume fraction x, on a series of percolating NiSiO2 granular films. At 5 K, the data for the metallic samples were fitted to power law dependencies of the forms, ϱxx ∝...
Persistent link: https://www.econbiz.de/10011058139
A large, by a factor of ≈103−104, enhancement of Hall effect in cosputtered magnetic granular metals such as (NiFe)x-(SiO2)1−x near the metal-insulator transition has been termed giant Hall effect (GHE). It is associated with a high resistivity which increases slowly with decreasing...
Persistent link: https://www.econbiz.de/10011058277
Thermoelectric power (Seebeck coefficient) measurements at room temperature have been made on composite Al-Ge films for aluminum volume fractions ranging from 20% to 100%. The critical metallic concentration φc at the metal-insulator transition is about φc⋍55%. These measurements were...
Persistent link: https://www.econbiz.de/10011058529
The electrical conductivity (σ), the thermal conductivity (λ) and the permeability (μ) are given as functions of the volume fractions for a series of sintered nickel samples. It is shown that σ, λ and μ data can all be fitted to a single equation with the same two morphology parameters ƒc...
Persistent link: https://www.econbiz.de/10011059964
The construction and the measurement of the conductivity of a series of two-dimensional dual media is described. The conductivity results are shown to obey both the defining relationship for dual media and a recently proposed general effective-media (GEM) equation, with two morphology...
Persistent link: https://www.econbiz.de/10011060373
The metal-insulator transition in composite Al-Ge films has been extensively studied experimentally. Using the superconducting properties of percolating clusters composed of small aluminum grains in the presence of a magnetic field, the critical metallic volume fraction φc(sc) for the...
Persistent link: https://www.econbiz.de/10011061913
Compressed discs made from graphite and, its mechanical but not electrical isomorph, boron nitride, as well as graphite-boron nitride powders, undergoing compression, are nearly ideal continuum percolation systems; as the ratio of their conductivities is 10−18 and the scatter of the...
Persistent link: https://www.econbiz.de/10011062748
Granular Al-Ge films, just on the metallic side of the critical volume fraction φc (50.7% Al), are found to have critical fields in excess of 1.5T at 0.47 K due to the fine granular nature of the Al. In barely insulating films where φc − φ 2.2% (φ is the volume fraction of aluminum),...
Persistent link: https://www.econbiz.de/10011064361