Kwok WK, Olsson RJ, Karapetrov G, Paulius LM, Moulton WG, Hofman DJ, Crabtree GW
Materials Science Division and Science and Technology Center for Superconductivity, Argonne National Laboratory, Argonne, Illinois 60439, USA.
Phys Rev Lett. 2000 Apr 17;84(16):3706-9. doi: 10.1103/PhysRevLett.84.3706.
The critical points in untwinned YBa(2)Cu(3)O(7-delta) crystals with dilute columnar defects are investigated. We find a convergence of a first order vortex melting line with an irreversibility line associated with the onset of the Bose glass critical regime at the lower critical point. In addition, we find that columnar defects raise the upper critical point, implying that vortex line meandering is a basic feature controlling its position.
