Superconducting and semiconducting thin films of La123 and their superlattices

Thin films of La123 and their superlattice with Y123 are deposited on various substrates for the first time. Thin films of La123 can be made semiconducting or superconducting within a small range of oxygen stoichiometry. A multiple target holder has been used for insitu processing of superlattice thin films. The ability of the La123 compound to exhibit either semiconductivity or superconductivity has been utilized to construct semiconductor/superconductor superlattice structures with Y123 X-ray diffraction studies have shown clearly the presence of two distinct type of layers in the superlattice films with a individual layer thickness of ∼120 and 300 Angstrom, although this did not happen for ∼24 Angstrom thickness of the individual layers. Rutherford backscattering experiments showed good quality of the films with channeling yields <10%. Resistivity measurements showed a Tc (onset) = 90 K and Tc(zero) = 85 K for the La123 as well as superlattice thin films