MICROSTRUCTURAL FEATURES AND SUPERCONDUCTING PROPERTIES OF MN-DOPED YBA2CU3O7-DELTA

Small additions of MnO2 up to 15 at. % in YBa2Cu3O7-delta in place of Cu have been carried out to study their influence on the superconducti ng properties. It has been found that transition temperature and micro structure of Mn-doped samples are highly sensitive to the sintering te mperature and Mn content. The normal state resistance increases with M n content. Microstructure shows plate-like grain growth for low Mn con tents (up to x = 0.05) at higher sintering temperature. XRD and micros tructure reveals the presence of additional Y2BaCuO5 and Ba3Mn2O8 phas es with an increase in Mn content. Also, reduction in the diamagnetic signal and broadening of transition is observed beyond certain Mn cont ent. A detailed discussion of microstructure, XRD, normalized resistan ce, and magnetic properties has been carried out in correlation with s intering temperature and Mn content.