Magnetic Domain Structure and Crystal Orientation Revealed by a Forescatter Detector and Electron Backscatter Diffraction

Imaging magnetic domains for soft magnetic materials using scanning electron microscopy (SEM) typically requires a specially modified setup. These modifications can include higher beam acceleration voltages, modifications of the sample and detector geometry, and/or specialized detectors to detect the spin polarization of secondary electrons [1,2]. In this research, a method is presented for imaging magnetic domains with type II magnetic contrast using a forescatter detector (FSD) attached to a commercial electron backscatter diffraction (EBSD) camera, with a resolution limit of approximately 200-300 nm. In addition to revealing the magnetic contrast, the EBSD system was used to provide complementary crystal orientation information, which helped to interpret the direction of alignment and fine structure of the magnetic domains. The analysis method was demonstrated on a non-oriented electrical steel (NOES) sample; a material typically used in the motor core of electric vehicle drivetrains.