We report the enhanced superconducting properties of double-chain based superconductor Pr2Ba4Cu7O15−δ synthesized by the citrate pyrolysis technique. The reduction heat treatment in vacuum results in the appearance of superconducting state with Tc=22-24 K, accompanied by the higher residual resistivity ratios. The superconducting volume fractions are estimated from the ZFC data to be 50∼55%, indicating the bulk superconductivity. We evaluate from the magneto-transport data the temperature dependence of the superconducting critical field, to establish the superconducting phase diagram. The upper critical magnetic field is estimated to be about 35 T at low temperatures from the resistive transition data using the Werthamer-Helfand-Hohenberg formula. The Hall coefficient RH of the 48-h-reduced superconducting sample is determined to be −0.5×10−3 cm3/C at 30 K, suggesting higher electron concentration. These findings have a close relationship with homogeneous distributions of the superconducting grains and improved weak links between their superconducting grains in the present synthesis process.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering