We have determined the structure of ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{\mathit{x}}$/${\mathrm{PrBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{\mathit{x}}$ and ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{\mathit{x}}$/${\mathrm{GdBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{\mathit{x}}$ high-${\mathit{T}}_{\mathit{c}}$ superlattices using a novel method to refine the structure from x-ray diffraction spectra. This technique allows quantitative determination of disorder in superlattices in good agreement with independent measurements where available. The results show that layer thickness fluctuations, interdiffusion, and strains are present in the high-${\mathit{T}}_{\mathit{c}}$ superlattices and cannot be neglected when studying the physical properties.

• Received 24 April 1992

DOI:https://doi.org/10.1103/PhysRevLett.69.2859