Flux pinning enhancement by room temperature plastic deformation on Hg-based ceramic superconductors

摘要

We report on the superconducting properties of plastically deformed Hg_(0.82)Re_(0.18)Ba_2Ca_2Cu_3O_(8 + #delta#) (T_c = 133 K) ceramics. The critical temperature, low field susceptibility, and irreversible magnetization have been carefully analyzed as a function of the plastic strain. It is shown that plastic deformation does not alter T_c, but results in a marked decrease of the screened sample volume; this is likely related to the reduction of the grain size by cracking. After correcting for this effect, the irreversible magnetization indicates an enhancement of flux pinning due to the deformation-induced defects-mainly dislocations; relaxation measurements confirm this result.