Interaction of a biosurfactant, Surfactin with a cationic Gemini surfactant in aqueous solution.

The interaction between biosurfactant Surfactin and cationic Gemini surfactant ethanediyl-1,3-bis(dodecyldimethylammonium bromide) (abbreviated as 12-3-12) was investigated using turbidity, surface tension, dynamic light scattering (DLS) and small angle neutron scattering (SANS). Analysis of critical micelle concentration (CMC) values in Surfactin/12-3-12 mixture indicates that there is synergism in formation of mixed Surfactin/12-3-12 micelles. Although Surfactin and 12-3-12 are oppositely charged in phosphate buffer solution (PBS, pH7.

Complex chiral modulations in FeGe close to magnetic ordering.

We report on detailed polarized small-angle neutron scattering on cubic FeGe in magnetic fields applied either along (transverse) the scattering vector or parallel (longitudinal) to the neutron beam. The (H, T) phase diagrams for all principal axes contain a segmented A-phase region just below the onset of magnetic order. Hexagonal Bragg-spot patterns were observed across the entire A-phase region for the longitudinal geometry.

SANS analysis of opal structures made by the capillary deposition method.

Small angle neutron scattering (SANS) is used to analyze the structure of opals and inverse opals made by the capillary deposition method. We show that there is no deformation in special lattice directions such as the growth direction and the support plane direction. However, effects of twinning of the dense-packed structure and plane-like lattice perturbations have been observed.

Neutron optical beam splitter from holographically structured nanoparticle-polymer composites.

We report a breakthrough in the search for versatile diffractive elements for cold neutrons. Nanoparticles are spatially arranged by holographical means in a photopolymer. These grating structures show remarkably efficient diffraction of cold neutrons up to about 50% for effective thicknesses of only 200   μm.

Grain-boundary-induced spin disorder in nanocrystalline gadolinium.

Based on experimental magnetic-field-dependent neutron scattering data, we have calculated the autocorrelation function of the spin misalignment of nanocrystalline (160)gadolinium. The analysis suggests the existence of two characteristic length scales in the spin system: the smaller one is about 5 nm and is attributed to the defect cores of the grain boundaries, whereas the larger length scale is of the order of the average crystallite size D = 21 nm and presumably describes the response of the magnetization to the magnetic anisotropy field of the individual crystallites.