Small angle neutron scattering study of the magnetic flux-line lattice in single crystal 2H-NbSe2

We report on a small angle neutron scattering study of the flux-line lattice in single crystal 2H-NbSe2. As the magnetic field is tilted away from the crystalline c axis, we find distortions in the flux lattice as would be expected for a mass anisotropy Γ=10.1±0.9. However, we find that the lattice orientation is in disagreement with the predictions of both anisotropic London and Ginzburg-Landau theories. The observed flux lattice orientation …