Experimental and methodic progress in ultra-small-angle polarised neutron scattering on novel magnetic materials

Ultra-small-angle scattering of polarised neutrons (USANSPOL) allows for the study of magnetic structure in the micrometre range. The technique takes advantage from the narrow angular width of the Bragg reflection curve of perfect crystals and is employed in a double-crystal configuration of channel-cut perfect silicon crystals. Polarisation of the neutron beam is obtained by placing magnetic prisms, which act as birefringent regions, between the monochromator and analyser crystal. Samples are placed between the polariser prisms and the analyser crystal. Scattering of spin-up and spin-down neutrons is recorded in a single measurement and identified by an angular shift of the irrespective scattering curves. We have developed a prototype sample environment and handling system by which anisotropic samples may be aligned in different orientations and be subjected to external magnetic fields and stresses. Here, we present new experimental results on iron-boron ribbons of varying composition with remarkable magnetostriction properties, highly promising for technological application, and methodic development.