Dual-axis 360° rotation specimen holder for analysis of three-dimensional magnetic structures

A dual-axis 360° rotation specimen holder was developed for use in reconstructing the three-dimensional (3D) distribution of a magnetic field using a combination of electron holography and tomography. Pillar-shaped specimens are used to obtain accurate reconstruction without a missing angle. The holder's rotation rod can be turned >360°; the pillar is set ±45° to the azimuth for both x- and y-axis rotation. Two rotation series of holograms in individual axes are recorded for vector field tomography. The two vector components of the magnetic field are reconstructed directly from the two series of holograms, and the remaining component is calculated using Maxwell's equation, div B = 0. As a result, all 3D magnetic fields are reconstructed.