Reports

A-Axis—Oriented YBa2Cu3O7/PrBa2Cu3O7 Superlattices

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Science  15 Feb 1991:
Vol. 251, Issue 4995, pp. 780-783
DOI: 10.1126/science.251.4995.780

Abstract

A modulated structure has been fabricated from high transition temperature superconductors where the individual CuO2 planes are composed of alternating superconducting and insulating strips. This structure is made by growing a-axis—oriented YBa2Cu3O7/PrBa2Cu3O7 superlattices by 90° off-axis sputtering on (100)SrTiO3 and (100)LaAlO3 substrates. Superlattice modulation is observed to a modulation wavelength of 24 angstroms (12 angstroms—YBa2Cu3O7/12 angstroms—PrBa2Cu3O7), both by x-ray diffraction and by cross-sectional transmission electron microscopy. Rutherford backscattering spectroscopy indicates a high degree of crystalline perfection with a channeling minimum yield of 3 percent. Quasi—one-dimensional conductivity should be obtainable in these structures.