Vortex flow and transverse flux screening at the bose glass transition
We study the vortex phase diagram in untwinned YBCO crystals with columnar defects. These randomly distributed defects are expected to induce a "Bose glass" phase of localized vortices exhibiting a vanishing resistance and Meissner effect for magnetic fields H( perpendicular) transverse to the columns. We directly observe the transverse Meissner effect using a Hall probe array. As predicted, the Meissner state breaks down at temperatures T(s) that decrease linearly as H( perpendicular) increases. However, T(s) lies far below the conventional melting temperature T(m) determined by a vanishing resistivity, suggesting a regime where vortices are effectively localized even when rotated off the columnar defects.
Smith
AW
The James Franck Institute and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA.
Jaeger
HM
Rosenbaum
TF
Petrean
AM
Kwok
WK
Crabtree
GW