LaNiO3 and Cu3Ge contacts to YBa2Cu3O7-x films

Abstract

Metallization of high-Tc superconductors using low resistivity metal oxides and Cu-Ge alloys has been investigated on high quality pulsed laser deposited epitaxial YBa2Cu3O7-x (YBCO) films. Epitaxial LaNiO3 (LNO) thin films have been grown on YBCO films at 700°C using pulsed laser deposition. The specific resistivity of LNO was measured to be 50 µΩ-cm at 300K which decreases to 19 µΩ-cm at 100K indicating good metallicity of the LNO films. The contact resistance of LNO-YBCO thin film interface was found to be reasonably low (of the order of 10-4Ω-cm2 at 77K) which suggests that the interface formed between the two films is quite clean and LNO can emerge as a promising metal electrode-material to YBCO films. A preliminary investigation related to the compatibility of Cu3Ge alloy as a contact metallization material to YBCO films is discussed. The usage of other oxide based low resistivity materials such as SrRuO3 (SRO) and SrVO3 (SVO) for metallization of high-Tc YBCO superconductor films is also discussed.