DC and AC Josephson effects observed in high-temperature superconductor YBaCuO

• Published in: Journal of low temperature physics Vol. 69; no. 3-4; pp. 313 - 323
• Main Authors: KUZNIK, J, ODEHNAL, M, SAFRATA, S, ENDAL, J
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-11-1987
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Physics; Proximity effects, weak links, tunneling phenomena, and josephson effects, adreev effect, sn and sns junctions; Superconductivity; Voltage current curve; Transition metal Compounds; Very low temperature; Transition metal; Background noise; Experimental study; Oxide ceramics; Niobium; Inorganic compound; Critical current; Josephson effect; Direct current; Barium Copper Yttrium Oxides Mixed; High temperature superconductor; Alternating current
• ISSN: 0022-2291; 1573-7357
• DOI: 10.1007/BF00682664

The observation of the dc and ac Josephson effect and quasiparticle tunnelling in the high-temperature superconductor YBaCuO is reported. The observation was made at 4.2K. These effects were observed in a junction made by a Nb tip pressed against a high-T sub c sample of YBaCuO ceramic. A clean dc Josephson effect with a critical current I sub c approx 2 mu A and the ac effect with Shapiro steps corresponding to V = (hf/2e)n were observed. The nature of the junction was not clear; however, it is suggested that all observed effects can be explained by assuming a singlet pairing state in the ceramic. A very peculiar noise behavior was also observed along the V--I characteristic. 15 ref.--AA