Vortex states in Bi2Sr2CaCu2O8+y with tilted columnar defects probed by Josephson plasma resonance

The interlayer phase correlation of vortices is studied in Bi2Sr2CaCu2O8+y with tilted and non-tilted columnar defects (CDs) by using the Josephson pl asma resonance under tilted fields. We compare the temperature dependence o f resonance field in Bi2Sr2CaCu2O8+y with the same density of CDs which are introduced at different angles from the c-axis. We also consider the field dependence of interlayer phase coherence. A larger enhancement of interlay er phase coherence is found in the sample with largely tilted CDs. The vort ex correlation length is estimated using the angular scaling. (C) 2001 Else vier Science B.V. All rights reserved.