Bi 2Sr 2CuO 6+ δ/ACuO 2 (A=Ca,Sr) superconducting multilayers obtained by Molecular Beam Epitaxy

Abstract

Bi-based superconducting multilayers, consisting of Bi 2Sr 2CuO 6+ δ (2201) layers alternately stacked with CaCuO 2 or SrCuO 2 layers, have been deposited by Molecular Beam Epitaxy (MBE) using co-deposition and growth interruption techniques. In situ Reflection High Energy Electron Diffraction (RHEED) has been used to monitor the surface of the different layers giving evidence of a two-dimensional growth mode. The layered structure of the samples has been confirmed by X-ray diffraction analyses. Resistive measurements have shown superconducting 2201/CaCuO 2 samples with critical temperatures strongly depending on the thickness of the CaCuO 2. The 2201/SrCuO 2 multilayers do not show a zero electrical resistance above 4.2 K, but the resistance vs. temperature curves present a sharp decrease around 60 K indicative of a superconducting onset.