Visualization of magnetic domain structure in FeSi based high permeability steel plates by neutron imaging

摘要

In the present work, a combined study with polarized neutron imaging (PNI) and neutron-grating interferometry based dark field imaging (DFI) experiments on grain oriented high permeability steel sample with 3% Si and 0.35 mm thickness is reported. With the combination of these two experimental techniques it was possible to obtain the complex picture of magnetic domain distribution and domain walls in the electric steel samples. With the PNI technique, the observed fringe pattern contrast may be correlated with basic magnetic domains. These magnetic domains are oriented anti-parallel with respect to each other and the different magnetic field in each domain may lead to fringe pattern contrast. The magnetic domains are disrupted at the grain boundaries, observed as discontinuities in the fringe pattern contrast. In comparison, with DFI measurements, we visualized scattering contrast from magnetic domain walls. A clear correlation between basic domains (from PNI) and domain walls (using DFI) is observed. In the current study we also demonstrate the potential of combining two differential experimental techniques to visualize and obtain collective information about magnetic domains and domain walls. (C) 2019 Elsevier B.V. All rights reserved.