Sequential Ion-Beam and Cluster-Ion Surface Processing of YBa₂Cu₃O7-δ

This paper presents the results of sequential irradiation of the YBa ₂ Cu ₃ O 7-δ superconducting layer of a 2G HTS tape using atomic and cluster argon ions. It is shown that two-stage irradiation with monomers at a grazing incidence angle of 85 ∘ made it possible to remove a-orientated crystallite protrusions, significantly reducing the root-mean-square (RMS) roughness. Subsequent surface processing with cluster ions at normal ion incidence results in smoothing of the surface topography in the range of spatial frequencies from 0.5 to 10 μ m ⁻¹ . It is worth noting that, within the framework of this method, the depth of the modified layer does not exceed 10–20 nm, which indicates that no structural damage is introduced into the bulk of the superconducting film.