Flux-Line Lattice Structures in Untwinned YBa2Cu3O

TL;DR

This study uses small angle neutron scattering to analyze the flux-line lattice in untwinned YBa2Cu3O, revealing lattice orientations, anisotropy, and field-dependent re-orientation behavior.

Contribution

It provides detailed neutron scattering data on flux-line lattice structures and anisotropy in untwinned YBa2Cu3O, including observations of lattice re-orientation under magnetic fields.

Findings

Diffraction spots show four orientations of a hexagonal flux-line lattice.

Anisotropy ratio of 1.18(2) was determined.

Field-dependent re-orientation occurs around 3T at 33° to c.

Abstract

A small angle neutron scattering study of the flux-line lattice in a large single crystal of untwinned YBa2Cu3O is presented. In fields parallel to the c-axis, diffraction spots are observed corresponding to four orientations of a hexagonal lattice, distorted by the a-b anisotropy. A value for the anisotropy, the penetration depth ratio, of 1.18(2) was obtained. The high quality of the data is such that second order diffraction is observed, indicating a well ordered FLL. With the field at 33 degrees to c a field dependent re-orientation of the lattice is observed around 3T.