Metastable states of a flux line lattice studied by transport and Small Angle Neutron Scattering

TL;DR

This study investigates the different metastable states of flux line lattices in low-temperature superconductors using transport measurements and Small Angle Neutron Scattering, revealing how cooling procedures affect lattice order and transport properties.

Contribution

It provides new insights into the metastable flux line lattice states and their dependence on cooling procedures, with detailed experimental analysis in specific low T_c materials.

Findings

ZFC FLL is ordered with narrow Bragg peaks and linear V(I) curves.

FC FLL shows two Bragg peaks and an S-shaped V(I) curve.

Transport properties are unaffected by bulk dislocations in Pb-In.

Abstract

Flux Lines Lattice (FLL) states have been studied using transport measurements and Small Angle Neutron Scattering in low T$_c$ materials. In Pb-In, the bulk dislocations in the FLL do not influence the transport properties. In Fe doped NbSe$_{2}$, transport properties can differ after a Field Cooling (FC) or a Zero Field Cooling (ZFC) procedure, as previously reported. The ZFC FLL is found ordered with narrow Bragg Peaks and is linked to a linear V(I) curve and to a superficial critical current. The FC FLL pattern exhibits two Bragg peaks and the corresponding V(I) curve shows a S-shape. This can be explained by the coexistence of two ordered FLL slightly tilted from the applied field direction by different superficial currents. These currents are wiped out when the transport current is increased.