The Fabrication of Josephson Junctions on Y-Ba-Cu-O Thin Films
Electrical contact properties between noble metals and Y-Ba-Cu-O (YBCO) thin films prepared by multi-target rf sputtering method on (100) SrTiO3 and (100) MgO substrates were investigated. The temperature dependence of the contact resistance below the critical temperature of YBCO films suggested the existence of an insulating layer at the Au/YBCO interface. On the other hand, heat treated Ag/YBCO interface gave a very low contact resistance which could not be detected within the resolution limit of our apparatus. Based on this finding, we tried to fabricate Josephson junctions using lead as a counter electrode on the YBCO thin films covered by a thin silver layer expecting that the proximity effect worked between silver and YBCO. A dc “superconducting current” with undetectable resistance and a highly hysteretic current voltage (I–V) characteristic were observed below the transition temperature of lead.
KeywordsCritical Current Density Josephson Junction Tunnel Junction YBCO Film RHEED Pattern
Unable to display preview. Download preview PDF.
- 1.H. Adachi, K. Hirochi, K. Setsune, M. Kitabatake and K. Wasa, Low-temperature process for the preparation of high Tc superconducting thin films, Appl. Phys. Lett. 51, 2263 (1987)Google Scholar
- 3.X. D. Wu, A. lnam, T. Venkatesan, C. C. hang, E. W. Chase, P. Barboux, J. M. ‘l’arascon and B. Wilkens, Low-temperature preparation of high Tc superconducting thin films, Appl. Phys. Lett. 52, 754 (1988)Google Scholar
- 6.T. Miura, Y. Terashima, M. Sagoi, K. Kubo, J. Yoshida and K. Mizushima, Effects of oxygen partial pressure on properties of Y-Ba-Cu-O films prepared by magnetron sputtering, presented at the American Vacuum Society 35th National Symposium, Atlanta (1988)Google Scholar