Observation of Well-Ordered Metastable Vortex Lattice Phases in Superconducting MgB2 Using Small-Angle Neutron Scattering

P. Das; C. Rastovski; T. R. O’Brien; K. J. Schlesinger; C. D. Dewhurst; L. DeBeer-Schmitt; N. D. Zhigadlo; J. Karpinski; M. R. Eskildsen

doi:10.1103/PhysRevLett.108.167001

Observation of Well-Ordered Metastable Vortex Lattice Phases in Superconducting MgB2 Using Small-Angle Neutron Scattering

P. Das, C. Rastovski, T. R. O’Brien, K. J. Schlesinger, C. D. Dewhurst, L. DeBeer-Schmitt, N. D. Zhigadlo, J. Karpinski, M. R. Eskildsen

DOI 10.1103/PhysRevLett.108.167001 · Physical Review Letters

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Abstract

The vortex lattice (VL) symmetry and orientation in clean type-II superconductors depends sensitively on the host material anisotropy, vortex density and temperature, frequently leading to rich phase diagrams. Typically, a well-ordered VL is taken to imply a ground-state configuration for the vortex-vortex interaction. Using neutron scattering we studied the VL in MgB2 for a number of field-temperature histories, discovering an unprecedented degree of metastability in connection with a known, second-order rotation transition. This allows, for the first time, structural studies of a well-ordered, nonequilibrium VL. While the mechanism responsible for the longevity of the metastable states is not resolved, we speculate it is due to a jamming of VL domains, preventing a rotation to the ground-state orientation.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
MgB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	39	Pressure not reported	unknown