Dielectric properties of (CuO, CaO2, and BaO)y/CuTl-1223 composites

Abstract

We synthesized (CuO, CaO 2 , and BaO) y /Cu 0.5 Tl 0.5 Ba 2 Ca 2 Cu 3 O 10-δ (y = 0, 5%, 10%, 15%) composites by solid-state reaction and characterized by x-ray diffraction, scanning electron microscopy, dc-resistivity, and Fourier transform infrared spectroscopy. Frequency and temperature dependent dielectric properties such as real and imaginary part of dielectric constant, dielectric loss, and ac-conductivity of these composites are studied by capacitance and conductance measurement as a function of frequency (10 kHz to 10 MHz) and temperature (78 to 300 K). The x-ray diffraction analysis reveals that the characteristic behavior of Cu 0.5 Tl 0.5 Ba 2 Ca 2 Cu 3 O 10-δ superconductor phase and its structure is nearly undisturbed by doping of nanoparticles. The scanning electron microscopy images show the improvement in the intergranular links among the superconducting grains with increasing nanoparticles concentration. Microcracks are healed up with the inclusion of these nanoparticles and superconducting volume fraction is also increased. The dielectric properties of these composites strongly depend upon the frequency and temperature. The zero resistivity critical temperature and dielectric properties show opposite trend with the addition of nanoparticles in Cu 0.5 Tl 0.

Zinc Nanoparticles at Intercrystallite Sites of (Cu0.5Tl0.5)Ba2Ca3Cu4O12−δSuperconductor

“…We have taken FTIR spectra in the range of 400-700 cm −1 in which the bands from 400 to 540 cm −1 are associated with the apical oxygen atoms and from 541 to 600 cm −1 are associated with CuO 2 planar oxygen atoms. The bands from 670 to 700 cm −1 are associated with O atoms in the charge reservoir layer [31][32][33][34]. But in the pure Cu 0.5 Tl 0.5 Ba 2 Ca 3 Cu 4 O 12− samples, the apical oxygen modes of types Tl-O A -Cu(2) and Cu(1)-O A -Cu(2) are observed around 415 cm −1 and 444∼456 cm −1 and CuO 2 planner modes are around 541 cm −1 .…”

Synthesis and superconductivity of (Ag) x /CuTl-1223 composites

“…The absorption bands in the range from 400 to 540 cm À 1 are associated with the apical oxygen atoms and in the range around from 541 to 600 cm À 1 are associated with CuO 2 planar oxygen atoms [32,33]. The absorption bands in the range from 670 to 700 cm À 1 are associated with O δ atoms in the charge reservoir layer [34][35][36][37][38]. The apical oxygen modes of type Tl-OA-Cu(2) and Cu(1)-O A -Cu(2) are observed around 430 cm À 1 and 460-499 cm À 1 and CuO 2 planner oxygen mode is around 536 cm À 1 in the pure Cu 0.5 Tl 0.5 Ba 2 Ca 2 Cu 3 O 10À δ samples.…”

Effect of Li on the Dielectric Properties of Bi2-xLixPb0.3Sr2Ca2Cu3Oy Compound

“…The two insulating Bi-O can act as charge reservoirs for hole or electron to the three Cu-O 2 layers [3]. The charge reservoir layer, grain-boundaries, impurities, and voids behave as dielectric media, which can be polarized by displacing the charge carriers from their equilibrium position with external applied field [4]. Although these materials have been characterized as superconductors, there has been little work on their dielectric properties.…”