Superconducting and Semiconducting Thin films of La₁₂₃ and₁₂₃ and their Superlattices

Abstract

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 Å, although this did not happen for ∼ 24 Å thickness of the individual layers. Rutherford backscattering experiments showed good quality of the films with channeling yields < 10%. Resistivity measurements showed a T_c (onset) = 90 K and T_c(zero) = 85 K for the La₁₂₃ as well as superlattice thin films.