Fig. 2

Epitaxial stabilization of Ba_0.95La_0.05SnO₃ films on (001)MgAl₂O₄ with an MgO template layer. a The X-ray diffraction (XRD) θ−2θ scan of \({\mathrm{BLSO}}_{{\mathrm{MgAl}}_{2}{\mathrm{O}}_{4}}^{\mathrm{MgO}}\) exhibits (001), (002), (003), and (004) diffraction peaks of BLSO and MgO, indicating the formation of (001)-oriented BLSO epitaxial films on (001)MgAl₂O₄ with a (001)MgO template layer. The XRD θ−2θ scan of \({\mathrm{BLSO}}_{{\mathrm{MgAl}}_{2}{\mathrm{O}}_{4}}\) indicates the formation of mixed crystallographic orientations of BLSO. The asterisks indicate the (002), (004), (006), and (008) diffraction peaks of MgAl₂O₄. As schematically shown in (b), c the XRD ϕ scans of (101)BLSO and (101) MgO show four diffraction peaks at the same ϕ angles as those of (202)MgAl₂O₄, indicating four-fold symmetrical in-plane matching. d The low full-width at half-maximum of 0.78° in the XRD ω-scans of (002)BLSO indicates high crystallinity of BLSO epitaxial films with an MgO template layer. e Reciprocal space mapping indicates the absence of strain in the BLSO film and MgO template layer on the MgAl₂O₄ substrate, given that the (204)BLSO and (204)MgO peaks are near the Q_x- and Q_z-values of their bulks (× symbols)