  The properties of the MoSr2YCu2O8 materials are found to systematically
change with the oxygen concentration determined by the sintering and annealing
conditions. The as-prepared (asp) sample is anti-ferromagnetically (AFM)
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 TC and the shielding fraction values obtained depend strongly
on the oxygen concentration. Annealing the asp material at 1030 C under ambient
oxygen atmosphere yields TC of 18 K, whereas further annealing at 650 C under
92 atm. of oxygen, shifts TC to 32 K. The AFM 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, TN < TC. This behavior
resembles most of the inter-metallic magneto-superconductors, but is in sharp
contrast to the iso-structural RuSr2GdCu2O8 system where TN > TC.
