x-ray scattering; magnetoelectric coupling; complex oxides; oxide molecular beam epitaxy; strongly correlated materials; ferroelectric field effect; x-ray spectroscopy; interfaces; Multiferroic heterostructures; metal oxides; magnetism; ferroelectricity; x-ray microscopy; magneto-optic Kerr effect; interfaces; thin films; manganites; barium titanate
Vaz C. A. F., Shin Y. J., Bibes M., Rabe K. M., Walker F. J., Ahn C. H. (2021), Epitaxial ferroelectric interfacial devices, in Applied Physics Reviews
, 8(4), 041308-041308.
The interface region separating different materials is often the site of modified electronic properties, as a consequence of symmetry breaking and electron transfer processes across the boundary. For example, at the interface between materials with different order parameters, a cross-link between such order parameters can develop that leads to new functional properties. From both basic science and applied physics perspectives, a basic level understanding of the mechanisms responsible for those modified properties at interfaces is of fundamental interest.In this proposal, we aim to control the correlated state of high quality, molecular beam epitaxy-grown Sr and Ba-doped LaMnO3 ultrathin films interfaced with ferroelectric and dielectric layers, by electrostatically modulating the charge carrier density in a field-effect device structure. The strategy for achieving large susceptibilities consists of choosing manganite compositions for which the system lies near a boundary between two ground states in the doping phase diagram. The main goal of this project is to use x-ray absorption spectroscopy and x-ray resonant scattering measurements to probe the spin and orbital structure of the interface as the system is driven across two competing ground states. This project will also further contribute to developing x-ray scattering and spectroscopy techniques to tackling new requirements for sample excitation and measurement geometries. The results of the present investigation will shed light on the exact mechanisms linking charge density (i.e., electron correlations) to the ground state of the system, including the onset of spin and orbital order, phase separation, and their connection to the transport and magnetic properties of the interface.