Force-free current-induced reentrant melting of the vortex lattice in superconductors

Abstract

When increasing a current j flowing along the vortex lines, we obtain both a gradual shift of the vortex-lattice melting transition (VLMT) to a lower magnetic field and also a rising reentrant melting line, both separating the vortex solid from the vortex-liquid phase. The upper branch of the VLMT merges with the predicted reentrant lower branch at a certain value j m e r g e of the force-free current. We also derive the entire VLMT diagram in (B,T,j) three-dimensional phase space, and propose possible applications of it-including a magnetic-sensitive current-controlled switch using Bi 2 Sr 2 CaCu 2 O 8 + δ tapes.