Fig. 2
Epitaxy and compressive strain. Colour code: DTO||YTO(hkl) with (hkl) = (100) (blue), (hkl) = (110) (black), (hkl) = (111) (red). Each column reports data related to the same (hkl) as labelled in the first row. a High-resolution \({2}{\vartheta} - {\omega}\) scans showing, from left to right, the (400), (440) and (444) reflections for different film thicknesses. b, c Room temperature high-resolution X-ray powder diffraction (XRD) reciprocal space maps (RMS) for the thickest sample of each series. Here, the two orthogonal Qx are the components of the reciprocal space vector aligned with the substrate in-plane edges. These RMS confirm the film is high quality, fully epitaxial, and fully strained along the two in-plane orientations. d Schematics of the Dy sub-lattice are shown, where the tetrahedra edges depict the Dy–Dy distances. In the pyrochlore cubic structure these are all identical. In each strained DTO||YTO(hkl) film, a different distortion is realised. Here, different colours represent different Dy–Dy distances (values are reported in Table 2). DTO Dy2Ti2O7, YTO Y2Ti2O7
