The S-s’-S and S-N-S type superconductive junctions on YBCO material

In this paper an S-s’-S and an S-N-S junctions were fabricated using the femtosecond laser. The femtosecond laser was used because it has a short pulse duration on a thin film material and can reduce the thermal degradation of a superconductive thin film material. The S-s’-S junction is a micron sized constriction with a width of 2.1 μm, while the S-N-S junction is a sub-micron sized constriction with a width of 816 nm. The S-N-S junction due to its sub-micron width experiences more local heating from the femtosecond laser and as a result the superconductive material in the center normalizes producing the S-N-S junction. Its normal resistance (Rn) shows exponential growth versus temperature behaving like a normalized metallic material. The S-s’-S junction has a micron width, is less damaged by the localized heating of the femtosecond laser in the center of the constriction and as a result produces a geometrically reduced superconductive phase s’ . The normal resistance versus temperature curve for the S-s’-S constriction remains constant in the lower temperature range and then increases in the high temperature behaving like a reduced superconductive material. The IcRn product for the S-s’-S junction begins at 13.1 mV at 6 K while the IcRn product for the S-N-S junction begins at 1.9 mV at 8 K. The IcRn products decrease with temperature. The novelty of the work is that the paper shows the Rn and IcRn behavior of an S-s’-S and S-N-S type junctions fabricated strictly with the femtosecond laser. The paper also shows the Shapiro steps of the junctions. The optical equipment used to shape the laser beam have been described. S-s’-S and S-N-S junctions were fabricated with the femtosecond laser. The S-s’-S has a width of 2.1 μ m , the S-N-S has a width of 816 nm . The normal resistance of the S-N-S shows exponential behavior like a normalized metallic material. The normal resistance for the S-s’-S is constant and then increases vs temperature like a reduced superconductor. The novelty is the R n and I C R n of the S-s’-S and S-N-S. • AFM images showing width of fabricated superconductive junctions. • I-V Characteristics of the S-s’-S and S-N-S superconductive junctions at 10 K and 8 K. • Rn Vs temperature variations for the S-s’-S and S-N-S type junctions. • IcRn Vs temperature variations of the S-s’-S and S-N-S type junctions. • Novel junctions fabricated with the femtosecond laser.