Imaging the Magnetic Configuration in 3D Structures

To fully understand a three-dimensional magnetic system, suitable imaging techniques are required. Traditionally, high spatial resolution imaging of magnetic configurations has been limited to surfaces and thin films. To overcome these limitations, we have developed tomographic techniques with synchrotron x-rays to look beyond the sample surface and probe the 3D magnetization configuration in magnetic materials.

To image the configuration of 3D magnetic structures with synchrotron x-rays, one first needs to measure a two-dimensional projection of the magnetic structure. Magnetic sensitivity is obtained using circularly polarized x-rays that are focused on the sample. To obtain 3D information on the magnetic state, several 2D projections, measured at different orientations of the sample, can be combined to obtain a 3D image using a self-developed reconstruction algorithm [1].

One of the main challenges facing the characterization of 3D magnetic systems is the vectorial nature of the magnetization. In particular, all three components of the magnetization vector field must be determined. To achieve maximum flexibility in terms of samples that can be measured, two experimental geometries can be used: dual-axis tomography or laminography, shown schematically in Fig. 1.