A new development in small-angle neutron scattering with polarization analysis allows us to directly extract the average spatial distributions of magnetic moments and their correlations with three-dimensional directional sensitivity in any magnetic field. Applied to a collection of spherical magnetite nanoparticles 9.0 nm in diameter, this enhanced method reveals uniformly canted, magnetically active shells in a nominally saturating field of 1.2 T. The shell thickness depends on temperature, and it disappears altogether when the external field is removed, confirming that these canted nanoparticle shells are magnetic, rather than structural, in origin.
Krycka, K.L., R.A. Booth, C.R. Hogg, et al. "Core-shell magnetic morphology of structurally uniform magnetite nanoparticles." Physical Review Letters 104: 207203.
American Physical Society
Physical Review Letters
Physics and Astronomy
Magnetic nanoparticles, Polarized neutron scattering