The lower critical field and the DC magnetization behaviour in RBa₂Cu₃O₇ superconductors

Abstract

The DC magnetization data in a compound belonging to RBa2Cu3O7 family are presented. The features in magnetic hysteresis curves arising from intreagrain and intergranular links are identified and distinguished, and understood in terms of a logical axtension of Bean's critical state model. The anomalies near H=O line are observed in the magnetic hysteresis curves and these are identified with a recent assertion of Ravi Kumar and Chaddah that Hc1 manifests itself as anomalous link in hysteritic part of the magnetization curve. The data presented yield Hc1 value of a few Oe and it is argued that the earlier quoted values of Hc1 are gross overestimates.