Applications of Coherent X-Ray Scattering to Two Important Problems in Condensed Matter Physics

In the last decades, the commissioning of high-energy, third-generation synchrotronspresents new opportunities for research with brilliant coherent X-ray beams. It allows us to study various systems’ structure and dynamics at shorter length scale than laser via diffraction patterns. In the Chapter 3, we adopted the laser technique Photon Correlation Spectroscopy to study the dynamical correlations of the spin-glass transition. We have implemented this method to observe and accurately characterize the critical slowing down of the spin orientation fluctuations in the classic metallic spin glass alloy CuMn over time scales of 100 to 103 secs. In the Chapter 4, we adopted the diffraction imaging method to retrieve the phase of the speckle pattern produced by the scattering of a coherent X-ray beam to reconstruct the image of samples at nanometer length scales. We have extended the oversampling methods and iterative schemes to use the full Distorted-Wave Born Approximation (DWBA) expression for the speckle pattern. The results obtained from detailed computer simulations of the scattering and reconstruction are very encouraging in showing that the method works. Verification with real experiments is planned