Polarization-dependent MAD holography: Nanoscale Magnetic Imaging of Nonperiodic Objects

We present a novel approach to the nanoscale imaging of nonperiodic magnetic structures by introducing x-ray polarization dependence to the multiple wavelength anomalous diffraction (MAD) phasing technique. Essential phase information can be extracted from the differences between coherent scattering patterns recorded at different x-ray wavelengths (on- or off-resonance) and polarizations. Combined with an iterative phase retrieval algorithm, the magnetization distribution can be reconstructed. Using left and right circularly polarized x-rays near the Co L3 edge, we successfully imaged the perpendicular magnetic worm domains of a Co/Pd multilayer sample within a 3 micron circular aperture. The absence of reference apertures and a resolution that is, in principle, only limited by the wavelength render this method attractive for polarization-dependent and element-specific studies in magnetism, correlated materials and polymer research. This research is supported by the U.S. Department of Energy, Office of Basic Energy Science.