title: Persistence of metastable vortex lattice domains in MgB2 in the presence of vortex motion.
abstract: Recently, extensive vortex lattice metastability was reported in MgB2 in connection with a second-order rotational phase transition. However, the mechanism responsible for these well-ordered metastable vortex lattice phases is not well understood. Using small-angle neutron scattering, we studied the vortex lattice in MgB2 as it was driven from a metastable to the ground state through a series of small changes in the applied magnetic field. Our results show that metastable vortex lattice domains persist in the presence of substantial vortex motion and directly demonstrate that the metastability is not due to vortex pinning. Instead, we propose that it is due to the jamming of counterrotated vortex lattice domains which prevents a rotation to the ground state orientation.
authors.affiliation: Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA.
authors.forename: C
authors.initials: C
authors.lastname: Rastovski
authors.affiliation: Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Schlesinger
authors.affiliation: Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60660, USA.
authors.forename: W J
authors.initials: WJ
authors.lastname: Gannon
authors.affiliation: Institut Laue-Langevin, 6 Rue Jules Horowitz, F-38042 Grenoble, France.
authors.forename: C D
authors.initials: CD
authors.lastname: Dewhurst
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: L
authors.initials: L
authors.lastname: DeBeer-Schmitt
authors.affiliation: Laboratory for Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland.
authors.forename: N D
authors.initials: ND
authors.lastname: Zhigadlo
authors.affiliation: Laboratory for Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland and Institute of Condensed Matter Physics, EPFL, CH-1015 Lausanne, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Karpinski
authors.affiliation: Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Eskildsen