Direct Observation of the Flux-Line Vortex Glass Phase in a Type II Superconductor

Abstract

The order of the vortex state in La1.9Sr0.1CuO4 is probed using muon-spin rotation and small-angle neutron scattering. A transition from a Bragg glass to a vortex glass is observed, where the latter is composed of disordered vortex lines. In the vicinity of the transition the microscopic behavior reflects a delicate interplay of thermally induced and pinning-induced disorder.

Grain boundaries in vortex matter

“…In addition, we have neglected the effect of isolated dislocations and their interactions with grain boundaries. Therefore at this stage the present theory should be seen mainly as a framework for a general physical mechanism, 47 supported by simulations 36,37 and by some experiments, 48 for vortex lattice melting.…”

“…47 and experimental evidence was reported for La 1.9 Sr 0.1 CuO 4 . 48 The paper is organized as follows. In Sec.…”

Vortex lattice disorder inYBa2Cu3O7−δprobed usingSaadaoui1, MacFarlane2, Salman3 et al. 2009Phys. Rev. B11130View full textAdd to dashboardCite

“…18 Such disorder in the VL can produce a symmetric lineshape, 38,50 and can broaden the field distribution significantly compared to that of the corresponding ordered state. 51 Weak random pinning or point-like disorder due to oxygen deficiency may slightly distort the VL, and may also broaden the lineshape.…”

Mixed state ofLa1.83Sr0.17CuOWojek1, Bosma2, Pomjakushina3 et al. 2011Phys. Rev. B8070View full textAdd to dashboardCite

“…Though, especially in relatively low magnetic fields La 2−x Sr x CuO 4 shows a rich vortex-matter phase diagram where also in the solid phases the vortices are subject to thermal fluctuations. 30 Therefore, at high temperatures the vortices might "hop" thermally activated between different pinning centers which causes the muons only to be exposed to an average field [thus leading to a broadened but still asymmetric P (B)] while at low temperatures these thermal fluctuations are reduced and more muon spins precess in the high static fields close to the vortex cores which have a substantial effective size in the very low applied magnetic field. This could explain the observed positive shifts in the first moment and the second central moment of the measured field distribution.…”