MAGNETIC-PROPERTIES OF Y1-XPRXBA2CU3O7-Y CRYSTALS - MAGNETIZATION ANDIRREVERSIBILITY LINE

The magnetic properties of Y1-xPrxBa2Cu3O7-y crystals where x varies f rom 0.15 to 0.7 are presented. There is a concentration region (0.3 le ss than or equal to x less than or equal to 0.5) where magnetic orderi ng and superconductivity is suggested to co-exist. This co-existence c an be explained as a consequence of the superposition of magnetism due to Pri ions and diamagnetism due to superconductivity in an inhomogen eous system. The peak at 9 K in a magnetic field of 4 T for x = 0.3 is explained as a manifestation due to magnetic ordering. For magnetic f ields larger than 0.15 T, the irreversibility line for x = 0.2 is foun d to lie above that for x = 0.15 even though T-c is lower. This is exp lained in terms of Pr ions suppressing superconductivity in their vici nity and acting as pinning centres.