ESR Investigations of (BaSnO3)x/(Cu, Tl) 1223 composite in the normal and superconducting state

(BaSnO3)(x)/Cu0.5Tl0.5Ba2Ca2Cu3O10-delta superconducting composites (0.00 <= x <= 1.50 wt.%) were prepared by the solid-state reaction technique. The crystalline structure and superconducting transition temperature were investigated by X-ray powder diffraction (XRD) and dc-electrical resistivity measurements, respectively. X-Band electron spin resonance (ESR) measurements were carried out at different temperatures 103 <= T <= 298 K. ESR spectra are dominated by a single asymmetric line corresponding to Cu2+ ions at the rhombic site. The temperature dependence of the g factors allowed the determination of the pseudo-gap onset temperature T*. The results of T* are compatible with those obtained from resistivity and thermoelectric power measurements. The contribution of delocalized electrons from Cu2+ ions in the disordered part of the impurity phases BaCuO2 and Ba2CuO3 is significant for the high addition of nanoparticles. Moreover, the number of spins N participating in ESR and the activation energy E-a were enhanced with the addition of BaSnO3.

Automated summary

The (BaSnO3)(x)/Cu0.5Tl0.5Ba2Ca2Cu3O10-delta superconducting composites were prepared by solid-state reaction technique, with the investigation conducted on crystalline structure and superconducting transition temperature using XRD and dc-electrical resistivity measurements. ESR measurements at different temperatures revealed a single asymmetric line dominated by Cu2+ ions. The results show that the contribution of delocalized electrons from Cu2+ ions is significant for high addition of nanoparticles, and the number of spins and activation energy were enhanced with the addition of BaSnO3.