Tuning the superconducting state in the magnetic MoSr2YCu2O8-delta materials

The properties of MoSr2YCu2O8-delta materials are found to systematically change with the oxygen concentration determined by the sintering and annealing conditions. The as-prepared (asp) sample is antiferromagnetically ordered at 16 K. The magnetic features are related to the Mo5+ sublattice. Annealing under an oxygen atmosphere induces superconductivity (SC) in the Cu-O planes, and the T-C and the shielding fraction values obtained depend strongly on the oxygen concentration. Annealing the asp material at 1030 degreesC under ambient oxygen atmosphere yields T-C of 18 K, whereas further annealing at 650 degreesC under 92 atm. of oxygen, shifts T-C to 32 K. The antiferromagnetic ordering, which coexists with SC state through effectively decoupled subsystems, is not affected by the presence or absence of the SC state. In all samples studied, T-NT-C.