A precise study of fluxoid-line lattice (FLL) in the intermediate mixed state (IMS) in a niobium-crystal sphere has been made with a neutron-scattering technique. Accurate FLL unit-cell size determinations are facilitated by the high angular resolution of the technique so that reversibility of the microscopic flux density with applied-field history in and near the IMS can be demonstrated for the first time. Structural changes associated with hysteresis in the IMS are revealed through integrated intensities and full widths at half-maxima of the FLL rocking curves.

• Received 17 May 1976

DOI:https://doi.org/10.1103/PhysRevB.15.4506