Small-angle neutron scattering study of the vortex lattice in superconducting LuNi2B2C

TL;DR

This study uses small-angle neutron scattering to analyze the vortex lattice in LuNi2B2C, revealing a square lattice with in-plane anisotropy and an exponential decay of the form factor at high magnetic fields.

Contribution

It extends SANS measurements to higher q-values and fields, providing detailed insights into the vortex lattice structure and form factors in LuNi2B2C.

Findings

Square vortex lattice observed up to high fields

Form factor decreases exponentially with field

In-plane anisotropy detected in vortex lattice

Abstract

We present studies of the magnetic field distribution around the vortices in LuNi2B2C. Small-angle neutron scattering measurements of the vortex lattice (VL) in this material were extended to unprecedentedly large values of the scattering vector q, obtained both by using high magnetic fields to decrease the VL spacing and by using higher order reflections. A square VL, oriented with the nearest neighbor direction along the crystalline [110] direction, was observed up to the highest measured field. The first-order VL form factor, |F(q10)|, was found to decrease exponentially with increasing magnetic field. Measurements of the higher order form factors, |F(qhk)|, reveal a significant in-plane anisotropy and also allow for a real-space reconstruction of the VL field distribution.