First Order Vortex Melting Transition in YBa_2Cu_3O_7-d Single Crystals in the Presence of Defects
Abstract
We investigate the effects of both point-like and correlated defects on the 1st order vortex melting transition in single crystals of YBa_2Cu_3O_7-d. We start with a clean untwinned single crystal that displays a 1st order melting transition and introduce point-like disorder with 9 MeV proton irradiation. We find that the transition gradually crosses over from 1st order to second order and that the melting transition Tm shifts down in temperature as the number of point defects is increased. We compare these results with a crystal that contains correlated defects in the form of twin boundaries. This work supported by NSF grant DMR-9624047 and the U. S. DOE, BES contract W-31-109-ENG-38.
- Publication:
-
APS Ohio Sections Spring Meeting Abstracts
- Pub Date:
- April 1999
- Bibcode:
- 1999APS..OSS...P11P