Papers by Keyword: Dielectric Measurements

Abstract: Information about the spatial distribution of the electric field can be obtained by measuring the electrode impedance as a function of the diameter of the electrolyte surrounding the electrode. The non-uniform distribution of the electric field around the electrode is supported by the variation of the geometry factor (GF) with the electrical conductivity and geometry of the volume conductor. A comparison of the values obtained for the GF from experimental data, from model calculations and simulations help to understand the non-uniform distribution of the electric field. The GF calculated from four-electrode-measurements is significantly higher. GF should be used with caution in calculations of the deep brain stimulation (DBS) electrode impedance.

Abstract: Ceramic samples of SrBi_4-xLa_xTi₄O₁₅ with x=0.025 is prepared by standard solid state reaction method. The phase formation is confirmed by X-ray diffraction (XRD) studies. The Dielectric and Impedance measurement has been performed in the temperature range 50°C to 600°C and the frequency range 1Hz to 1MHz. The Curie temperature is found to decrease from 535°C to 505°C. The Cole-Cole plots are semi circles in the temperature range 450°C to600°C. The relaxation time is decreased with increase of temperature. The investigations on this material at high temperatures and frequencies reveal its stable behavior.

Abstract: The ferroelectric and electrical properties of potassium nitrate (KNO3): polyvinylidene fluoride (PVDF) composite layers prepared by melt press method have been studied. The stability of ferroelectric phase (phase –III) of potassium nitrate (KNO3) in the composite layers at room temperature have been analyzed. The temperature dependence of ferroelectric hysteresis loop (P-E) characteristics have been investigated in the composite layers. The electrical conductivity (σ) and dielectric behaviour of composite layers have been characterized. The conductivity and dielectric variation with temperature during heating and cooling modes has been found to provide the knowledge of phase transition in the composite. The capacitance –-voltage (C-V) and conductance - voltage (G-V) characteristics clearly show the ferroelectric butterfly loop, which is attributed to the features of ferroelectricity in the composite layers at room temperature. The coexistence of ferroelectric phase (phase III) with paraelectric phase (phase II) has also been observed at room temperature in the composite layers during dielectric and conductivity measurements.