Fig. 1

X-ray diffraction imaging of buried ferroelectric domains in a micro-capacitor configuration. a Schematic of the X-ray diffraction microscope (XDM), the scattering geometry, and characteristics of the sample (not drawn to scale). The imaging contrast of XDM is determined by the scattering vector, q = k _out − k _in, where k (\(|\varvec{k}| = 2\pi /\lambda\)) is the wavevector of the X-ray wavefield (\(\varvec{\lambda}\approx 1.2\) Å). A side view of the device indicates the thickness of the metallic electrodes [top Pt, bottom SrRuO₃ (SRO)], and the ferroelectric thin-film BiFeO₃ (BFO) that was grown on single crystal SrTiO₃ (001). b Optical image of the device showing the Pt electrode patterning (top view). c Reciprocal space map (RSM) near STO 002 Bragg reflection. All reciprocal space coordinates are expressed in terms of SrTiO₃ reciprocal lattice units (r.l.u). The BFO 002 Bragg reflection is offset in the HK-plane with respect to STO due to growth on a substrate with a high miscut angle (~4°, direction along STO [110]). d XDM images taken at different Bragg reflections of BFO (left: 002, right: 103). Spatial variations in the diffracted intensities are due to the presence of considerable lattice rotations (mosaicity) and epitaxial strain relaxation due to the large thickness of the film. Boxes in the images outline different mosaic blocks. The similarity in diffraction contrast between XDM images at G ₀₀₂ and G ₁₀₃ provide direct evidence for the mono-domain configuration of the ferroelectric thin-film (in agreement with RSM around STO 003, data not shown). The color bar indicates normalized diffracted intensity