X 線フーリエ変換ホログラフィー法による磁性薄膜の磁区構造観察

抄録

  X-ray Fourier transform holography (FTH) is one of the promising techniques for imaging of magnetic nanostructures. Coherent X-rays are used to record an interference pattern (hologram) of the object and reference waves, and a real-space image can be reconstructed by a simple inverse Fourier transform to the measured hologram. Thus, the FTH allows lensless imaging in a nanometer resolution, comparable to X-ray wavelengths, in principle. Magnetic contrast can be obtained using circularly polarized X-rays, which interact with electron's magnetic moments to give measurable dichroic signals in absorption/scattering intensities. FTH has several advantages over other magnetic imaging techniques; in particular, in-situ observation in strong magnetic fields is feasible since it is a photon-based probe. This article describes the principle of FTH, benefits from the technique, and recent highlights including in-situ imaging of sudden formation of local magnetic domain clusters, the microscopic origin of the Barkhausen effect, in a perpendicular magnetic film.