"Understanding nanoscale correlations in complex oxide heterostructures"
Complex oxide heterostructures provide access to emergent functional and structural phases which are not present in the bulk constituent materials. Controlling ionic distribution, stoichiometry, and epitaxial strain in complex oxide heterostructures have been utilized to significantly alter the electronic, magnetic, and structural properties. However, in order to fully understand and tailor nanoscale functionalities of correlated materials, detailed access to the nanoscale regime, correlation length scales and their temporal evolution is required. In this talk, I will discuss advanced synchrotron characterization techniques used by my group to investigate nanoscale properties of complex oxides heterostructures. The first part of my talk will focus on Gd/La0.67Sr0.33CoO3 (LSCO) heterostructures, which have shown promises for magneto-ionic control of functional properties through the presence of oxygen getter layers such as Gd. We have utilized x-ray nanodiffraction to directly image the nanoscale morphology of LSCO thin films as they are progressively transformed from the equilibrium perovskite phase to the metastable brownmillerite (BM) phase with increasing Gd and Al thickness. The second part of my talk will focus on temporal evolution of domain fluctuations and dynamics in BaTiO3 thin films, an archetypical ferroelectric material. By using coherent x-ray scattering technique, we compare domain fluctuations between second and first order phase transition in this material. The significant influence of heterogeneities on pathways of transition in both systems show the importance of nanoscale studies in correlated material systems.