Growth characteristics of HgBa2CaCu2O6 superconducting films on CeO2-buffered YSZ single crystals: an assessment for coated conductors

Superconducting HgBa2CaCu2O6 (Hg-1212) films have been fabricated on CeO2-buffered YSZ single-crystal substrates using a two-step cation-exchange process. XRD analyses show that the Hg-1212 films are crystalline and grow epitaxially on these CeO2/YSZ substrates. Although Tc's of these films are approximately 122 K, Jc's fall far below expected values. The reason for these low-Jc values is explained by the observations of a cracked surface morphology in the superconducting layers. The likely mechanism for formation of the cracks and implications for the development of Hg-based coated conductors are discussed. 6 refs.