Effect of Vanadium Substitution on the Dielectric Properties of Glass Ceramic Bi-2212 Superconductor

摘要

Glass ceramic superconductors were prepared by the melt-quenching method. The frequency and temperature dependence of dielectric constant (epsilon'), dielectric loss (epsilon") and loss tangent (tan delta) of these superconductors were investigated in the frequency range of 10 kHz-10 MHz and temperature range of 80-300 K using the capacitance-voltage (C-V) and conductance-voltage (G/w-V) measurements. Effect of vanadium on bulk properties, dc electrical resistivity (rho) and ac electrical conductivity ((sigma)_(ac)) of these superconductors were also investigated. The experimental results showed that epsilon', epsilon" and (sigma)_(ac) were strongly temperature and frequency dependent. Negative capacitance (NC) phenomenon has been observed and it is believed that the negative capacitance effect is due to polarization effect. The results can be concluded to imply that the interfacial polarization can occur more easily at low frequencies consequently contributing to the deviation of the dielectric properties and ac electrical conductivity of Bi_(2)Sr_(2)Ca_(1)Cu_(2)O_(delta) and Bi_(1.9)V_(0.1)Sr_(2)Ca_(1)Cu_(2)O_(delta) superconductors.