Y-Ba-Cu-O/Dy-Ba-Cu-O superlattices: A first step towards the artificial construction of high-Tcsuperconductors

We have for the first time epitaxially grown superlattices of Y-Ba-Cu-O/Dy-Ba-Cu-O by dc magnetron sputtering onto ${\mathrm{SrTiO}}_3$ and MgO substrates. The wavelengths range from 24 (twice the c axis) to 300 Å and x-ray diffractograms show satellite peaks characteristic of multilayers for each wavelength. The 24-Å-wavelength sample consists of, on the average, alternate planes of Y and Dy. The multilayers are superconducting with ${\mathrm{T}}_{\mathrm{c}0}$’s between 85 and 89 K, transition widths of 2 K, and resistivity ratios of about 3.