We analyze the current dynamics of a superlattice Bloch oscillator under conditions where, in addition to the dc bias field causing a negative differential ac conductivity, a similarly strong ac field is present, at a frequency somewhat below the Bloch frequency associated with the dc field. The differential conductivity at the ac drive frequency is then negative, but, because of the strong non...

nanoparticles of zirconium(iv) tungstate are prepared by chemical co-precipitation method. thecharacterizations have been carried out by tg/dta, dsc, afm, xrd, ftir and uv-vis spectrum. plspectrum shows two emission bands at 350 nm and at 477 nm. the effects of frequency on the dielectricbehavior and ac electrical conductivity have been studied. the dielectric constant is found to be 119.43 at1...

Using the CTRW approximation the simplest possible nontrivial model of ac hopping conductivity in disordered solids, is constructed. The model predicts universality of the frequency-dependent conductivity, independent of temperature, chemical composition, and conductivity mechanism, in reasonably good agreement with experiments. It is shown that all qualitative features of experimental ac hoppi...

zno nanorod was prepared by microwave assisted method. the crystal structure of the nano powders were confirmed by x-ray diffraction analysis and the mean particle size was estimated by the scherrer,s formula .the surface morphology of the nano particles were analyzed by   using sem . the absorption spectrum of the material in the uv-vis range was recorded .the energy band gap of the material w...

The latest experiments have confirmed the theoretically expected universal value πe/2h of the ac conductivity of graphene and have revealed departures of the quasiparticle dynamics from predictions for the Dirac fermions in idealized graphene. We present analytical expressions for the ac conductivity in graphene which allow one to study how it is affected by interactions, temperature, external ...

Nanoparticles of zirconium(IV) tungstate are prepared by chemical co-precipitation method. Thecharacterizations have been carried out by TG/DTA, DSC, AFM, XRD, FTIR and UV-Vis spectrum. PLspectrum shows two emission bands at 350 nm and at 477 nm. The effects of frequency on the dielectricbehavior and ac electrical conductivity have been studied. The dielectric constant is found to be 119.43 at1...

The paper presents experimental studies of dielectric properties of nanofluids based on ethylene glycol and SC-TiO2 nanoparticles with average size of 15-40 nm with various mass concentrations. The dielectric permittivity both real part and imaginary part as a function of temperature and frequency were measured. Also, dependence ac conductivity on frequency, temperature, and mass concentration ...

This paper studies the AC conductivity and permittivity of hydroxyapatite (HA)-based ceramics from 0.1 Hz-1 MHz at temperatures from room temperature to 1000 degrees C. HA-based ceramics were prepared either as dense ceramics or in porous form with interconnected porosity and were sintered in either air or water vapour. Samples were thermally cycled to examine the influence of water desorption ...

A Polyaniline/Manganese dioxide (PANI/MnO2) nanocomposite contains five weight percentages of MnO2. It has been successfully prepared by in situ polymerization. The structural, optical, and conductivity of nanocomposites remain relative to changes with respect to the weight percentage of MnO2. The structural, morphological, optical, and electrical conductivity i...