Direct observation of the flux-line vortex glass phase in a type II   superconductor
  The order of the vortex state in La_{1.9} Sr_{0.1} CuO_{4} 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. 
U. Divakar, A.J. Drew, S.L. Lee, R. Gilardi, J. Mesot, F.Y. Ogrin, D.   Charalambous, E.M. Forgan, G.I. Menon, N. Momono, M....