Direct Evidence for Edge-Contaminated Vortex Phase in a Nb Single Crystal using Neutron Diffraction

Helen A. Hanson; Xi Wang; Ivo K. Dimitrov; Jing Shi; Xinsheng Sean Ling; Charles F. Majkrzak; Brian B. Maranville; Mark Laver; Uwe Keiderling; Margarita Russina

arXiv · 1103.1273

Direct Evidence for Edge-Contaminated Vortex Phase in a Nb Single Crystal using Neutron Diffraction

Helen A. Hanson·Xi Wang·Ivo K. Dimitrov·Jing Shi·Xinsheng Sean Ling·Charles F. Majkrzak·Brian B. Maranville·Mark Laver·Uwe Keiderling·Margarita Russina

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Abstract

We report the first direct observation of a disordered vortex matter phase existing near the edge of a bulk type-II superconductor Nb using a novel position-sensitive neutron diffraction technique. This "edge-contaminated" vortex state was implicated in previous studies using transport techniques and was postulated to have played a significant role in the behavior of vortex dynamics in a wide range of type-II superconductors. It is found that upon thermal annealing, the vortex matter in the bulk undergoes re-ordering, suggesting that the edge-contaminated bulk vortex state is metastable. The edge vortex state remains disordered after repeated thermal annealing, indicating spatial coexistence of a vortex glass with a Bragg glass. This observation resolves many outstanding issues concerning the peak effect in type-II superconductors.

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Helen A. Hanson, Xi Wang, Ivo K. Dimitrov, Jing Shi, Xinsheng Sean Ling, Charles F. Majkrzak, Brian B. Maranville, Mark Laver, Uwe Keiderling, Margarita Russina. 2011-03-08. Direct Evidence for Edge-Contaminated Vortex Phase in a Nb Single Crystal using Neutron Diffraction. https://arxiv.org/abs/1103.1273

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