Polarized neutron diffraction with ex-situ $^3$He neutron spin filter and two-dimensional detector for noncollinear incommensurate magnetic order
Year: 2026
Type: preprint
Abstract: Polarized neutron scattering has been widely used for studying magnetic orders in condensed matter. A typical setup for this technique is a triple-axis spectrometer with a ferromagnetic single-crystal monochromator and analyzer, which is suited for point-by-point measurements within the horizontal scattering plane. However, this setup cannot fully meet the demands of recent studies on complex magnetic orders with emergent cross-correlated phenomena. For instance, multiferroics, magnetic skyrmions, and other topologically nontrivial magnetic orders tend to have incommensurate magnetic modulation vectors running along various directions in reciprocal space, which cannot be captured by measurements restricted to the horizontal scattering plane. To overcome these limitations, we have developed an experimental setup combining a $^3$He neutron spin filter ($^3$He-NSF) and a two-dimensional (2D) detector, which enables us to analyze the polarization of neutrons scattered away from the horizontal plane. We also establish a data reduction procedure to convert the 2D intensity maps into three-dimensional intensity distributions in reciprocal space, correcting for the effect of imperfect $^3$He polarization. This method is applied to single-crystal diffraction measurements on the multiferroic material Mn$_3$WO$_6$, which exhibits complex incommensurate magnetic orders. We have successfully observed polarization-dependent intensities of out-of-plane incommensurate magnetic reflections, demonstrating the effectiveness of the present method for analyzing complex magnetic structures.
Source: arXiv (Cornell University)
Institutions: Japan Atomic Energy Agency, Japan Proton Accelerator Research Complex, The Institute for Solid State Physics, The University of Tokyo, The University of Tokyo, High Energy Accelerator Research Organization, Institute of Materials Structure Science, Tohoku University, Institute for Materials Research, Tohoku University, RIKEN Center for Emergent Matter Science
Language: English
Subfield: Radiation
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7220971397