Entanglement of solid vortex matter: a boomerang-shaped reduction forced by disorder in interlayer phase coherence in Bi2Sr2CaCu2O8+y

Phys Rev Lett. 2008 Jul 11;101(2):027003. doi: 10.1103/PhysRevLett.101.027003. Epub 2008 Jul 10.

Abstract

We present evidence for entangled solid vortex matter in a glassy state in a layered superconductor Bi2Sr2CaCu2O8+y containing randomly splayed linear defects. The interlayer phase coherence--probed by the Josephson plasma resonance--is enhanced at high temperatures, reflecting the recoupling of vortex liquid by the defects. At low temperatures in the vortex solid state, the interlayer coherence follows a boomerang-shaped reentrant temperature path with an unusual low-field decrease in coherence, indicative of meandering vortices. We uncover a distinct temperature scaling between in-plane and out-of-plane critical currents with opposing dependencies on field and time, consistent with the theoretically proposed "splayed-glass" state.