Intrinsic Josephson junction

The formation of built-in Josephson junctions or intrinsic Josephson junctions (ITJ) along the c-axis in Bi2212 was claimed by Kleiner et al. (1992) and Kleiner and Muller (1994), who performed microwave emission experiments in small single crystals. 

The intrinsic sampler resolution is essentially determined by the ratio of current density to specific capacitance of a Josephson junction pulser contained in the sampling circuit. For picosecond resolution with existing helium temperature superconducting technologies, junction current densities are approaching 104 to 105 A/cm2. The upper end of this is at the limit that has presently been demonstrated for the YBaCuO superconductor itself at 77 K, so achieving such density in a junction will be a major challenge. 

The 7-K characteristics of small stacked junctions of underdoped Bi2212 single crystals were investigated by Tanabe et al. (1996). The I—V characteristic of an intrinsic junction stack exhibits a superconducting branch and a large number of branches in the resistive state. This structure can be explained by assuming that the I-V characteristic of every individual junction exhibits a superconducting and a resistive branch, similar to the /- V characteristics of standard Josephson junctions. 

Most electronic applications are based on the turmel effect between two superconductors that are separated by a weak (isolating) link that is only a few atomic layers thick. Currently, Nb and A1 are used preferably to build Josephson tunnel junctions (JTJs), whereas ceramic superconductors are stiU less common. However, the situation may soon change following the discovery of coherently emitting tera-Hertz radiation of intrinsic BSCCO JTJs (Ozyuzer et al., 2007). Some aspects of electronic applications are considered in detail at this point. 

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