Bragg Coherent X-ray Diffraction for Domain Imaging in Oxides
June 19th, 2019 IAN ROBINSON UCL - London’s Global University

The Bragg Coherent Diffraction Imaging (BCDI) method we use for imaging microstructure in crystals will be outlined in this seminar. BCDI’s greatest strength is to reveal 3D phase-contrast images of the interiors of crystals with image resolution in the 30nm range. It achieves this through the projection of lattice displacements onto the diffraction Q-vector, showing up as a phase shift on a very sensitive scale: one lattice constant results in a phase shift of 2π. Using this new channel of information about the detailed structures of crystals, we have found striking patterns of phase nano-domains within otherwise solid-looking crystals of micron dimension. Since almost all materials are made up of microcrystals, this method has wide application in materials science and engineering and lies at the heart of a case for a new beamline at NSLS-II.

I will discuss various materials studied by BCDI: domains introduced in Au by interdiffusion of Cu, faulted misfit domains on the surface of Au induced by Fe diffusion, insect virus crystals, SAPO-34 zeolite catalyst crystals and the Perovskite La0.5Ca0.5MnO3 (LCMO). Lastly, the potential of time-resolved imaging of internal crystal motions will be explored using Free-electron Laser techniques.

Seminar, June 19, 2019, 12:00. ICFO’s Seminar Room

Hosted by Prof. Simon Wall