In situ x-ray nano-imaging of polarization evolution in epitaxial 0.7PbMg_1/3Nb_2/3O₃-0.3PbTiO₃ thin film heterostructures

High electromechanical coupling in relaxor ferroelectrics such as 0.7PbMg_1/3Nb_2/3O₃-0.3PbTiO₃ (PMN-PT) have nanoscale polar structures, which are believed to facilitate polarization rotation. In this study, we utilize hard x-ray nanodiffraction to simultaneously measure real and reciprocal space of epitaxial thin film FeGa/PMN-PT/Ba_0.5Sr_0.5RuO₃/GdScO₃ (110) devices under applied DC electric field. Dark-field imaging by the x-ray nanoprobe allows us to attribute strain and lattice rotation information from multiple Bragg reflections over the same spatial region of a device. We observe different localized changes to the crystal structure of PMN-PT, and provide a discussion on the distribution of phase coexistence throughout the device.