Copper rich Y–Ba–Cu–O superconductors

Abstract Copper rich compounds with YBaCu 12 O 15 stoichiometry were synthesized at 900°C under oxygen rich atmosphere and annealed at 350°C in oxygen flow during 1, 3 and 60 days. Results of AC magnetic susceptibility, thermomagnetic analysis and electron paramagnetic resonance spectroscopy indicate multiphase materials containing the phases YBaCu-123 and YBaCu-247. Critical temperatures were determined by AC magnetic susceptibility and confirmed by EPR measurements.