fig4

Figure 4. Thickness-dependent XRD analyses of freestanding BaTiO₃/BaZrO₃ membrane heterostructures on mica substrates. (A) The thickness-dependent XRD θ-2θ results of the as-grown freestanding ferroelectric BaTiO₃/BaZrO₃ membrane heterojunctions. (B) The thickness-dependent rocking-curve measurements of the BaTiO₃ (200) peaks in freestanding BaTiO₃/BaZrO₃ heterojunctions. (C) Thickness-dependent evolution of out-of-plane lattice parameters of the BaTiO₃ and BaZrO₃ layers in BaTiO₃/BaZrO₃ bilayer membranes in comparison with bulk BaTiO₃ and BaZrO₃. (D) A plot of FWHM values of the BaZrO₃ (002) and BaTiO₃ (200) peaks as a function of the BaTiO₃ film thickness. Error bars in (C and D) represent standard errors in the obtained lattice parameters and FWHM values, which are extracted from the Lorentzian fits of the XRD θ-2θ and rocking-curve results in (A and B), respectively.