First-order transition lines in micro-sized high Tc superconductors

M. I. DOLZ; N. R. CEJAS BOLECEK; Y. FASANO; M. KONCZYKOWSKI; H. PASTORIZA

Trieste

Workshop; POSTER en Workshop on Probing and Understanding Exotic Superconductors; 2014

ICTP - International Centre for Theoretical Physics

The persistence of the first-order transition line in the phase diagram of mesoscopic Bi2Sr2CaCu2O8 vortex matter is detected down to a system size of less than hundred vortices. Precise and highly-sensitive to bulk currents AC magnetization techniques proved to be mandatory in order to obtain this information. The location of the vortex matter first-order transition lines is not altered by decreasing the sample size down to 20 micrometers. Nevertheless, the onset of irreversible magnetization is affected by increasing the sample surface-to-volume ratio producing a noticeable enlargement of the irreversible vortex region above the second-peak transition.