Small-angle neutron scattering study of the vortex lattice in superconductingLuNi2B2C

Abstract

We present studies of the magnetic field distribution around the vortices in ${\text{LuNi}}_{2}{\text{B}}_{2}\text{C}$. 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, $|F({q}_{10})|$, was found to decrease exponentially with increasing magnetic field. Measurements of the higher-order form factors, $|F({q}_{hk})|$, reveal a significant in-plane anisotropy and also allow for a real-space reconstruction of the VL field distribution.