Dielectric properties of Cu0.5Tl0.5Ba2Ca2Cu3O10-δ superconductor added with nano-Fe2O3

Abstract

A series of high-temperature superconducting samples of type Cu0.5Tl0.5Ba2Ca2Cu3O10-δ, (Cu0.5Tl0.5)-1223, added with nano-Fe2O3 (0.01.0 wt. %) was prepared by a solid-state reaction technique via short time preparation procedure and under ambient pressure. The prepared samples were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) for phase analysis and microstructure examination. The volume fraction results indicated that nano-Fe2O3 addition was significant in enhancing the formation rate of the (Cu0.5Tl0.5)-1223 phase, especially for x ≤ 0.2 wt. % samples. The electrical resistivity of the prepared samples was measured by the conventional four-probe technique from room temperature down to the zero superconducting transition temperature (T0). An increase in the superconducting temperature, Tc, is observed up to x = 0.2 wt. %, followed by a systematic decrease with increasing nano-Fe2O3 addition. The dielectric constants (ε' and ε''), dissipation factor (tan Δ) and real ac conductivity (σ'ac) were investigated as a function of temperature (113293 K) and frequency (102106 Hz). The results clarified that all these dielectric parameters show a strong dispersion with temperatures at low and moderate frequency ranges. Moreover, they are strongly dependent on nano-Fe2O3 addition. Furthermore, the high content of nanoFe2O3 addition (x = 1.0 wt. %) enhanced ε' and reduced tan D of (Cu0.5Tl0.5)-1223 phase, which is a desirable demand for practical applications.