Disorder, History Dependence and Phase Transitions in a Flux Lattice
The vortex lattice is an ideal system to study the competition and interplay between interaction and disorder. New results on 2H-NbSe_2 (in samples of progressively increasing pinning) elucidate how pinning alters the phase boundary separating the "ordered" and "disordered" states of the flux lines and causes a novel disorder-induced transition. A generic magnetic phase diagram of a type II superconductor.