Peak effect in an irradiated microbridge of Bi-2212 single crystal: evidence for a Bragg Bose glass?

Abstract

We have investigated I– V characteristics at very low temperature on a micro-bridge in a Bi-2212 single crystal with columnar defects patterned by laser ablation. We have shown that the critical current I C presents a maximum when increasing the applied magnetic field. This maximum is located below the matching field at a filling fraction f= B Max/ B Φ=0.8. The transverse Meissner effect (TME) has also been checked by tilting the magnetic field away from the tracks. Contrary to the low field regime ( f<0.8) where the vortex are strongly localized, the transverse component of the magnetic field is not screened anymore when the parallel one is higher than B Max. It suggests that the vortex system could be considered as a weak Bose glass with interstitial vortices. It suggests that the vortex system could be considered as a weak Bose glass with interstitial vortices. Finally, our results strongly support the existence of a typical vortex phase at low temperature and low magnetic field.