Oxygen Stoichiometry effect on magnetic properties of Yba₂Cu₃O₇_δ superconductor

Abstract

Magenetic hysteresis loops measurements on single crystal and polycrystalline YBa₂Cu₃Ox high-Tc ceramic reveals that the energy losses increase with the maximum cycling field, in clear disagreement with behavior expected from Bean's model. The magnetic energy losses in Field Cooled (FC) state is observed to be lower than energy losses in Zero Field Cooled (ZFC) state, reflecting that the FC state is a more ordered state. The remanent magnetization, initially increases rapidly then approaches saturation gradually. For single crystal, the energy losses and the remanant magnetization along the c-axis have been observed to be greater than in the ab-plane. Upon varying the oxygen content (x) in polycrystalline YBa₂Cu₃Ox, the energy losses increases with increasing x, reaching a maximum near x=6.64 then decreases upon further increase of oxygen content. Calculation of critical current density (Jc) using hysteresis loop and Bean's model, reveals that Jc increasing linearly with oxygen content.