AMBIENT-PRESSURE SYNTHESIS OF SUPERCONDUCTING YBA2CU4O8

Abstract

A highly homogeneous and monophasic high-T(c) superconductor YBa2Cu4O8 with T(c(zero)) of 75 K and fine grain size has been synthesized at 1 atm of oxygen via a route employing polymeric ethylene glycol/citric acid (EG/CA) precursors. In addition to the chemistry involved in the preparation, the effect of preparation temperature, time of processing and EG/CA ratio in the precursor on the formation and superconductivity of the 124 phase was systematically investigated. The results of X-ray diffraction, the temperature dependence of resistivity and dc magnetic susceptibility, and the SEM microstructure studies on 124 synthesized under different conditions were also summarized.