Josephson tunneling

The theory foresees the possibility of coulomb blockade phenomenon in such junctions. Averim and Likharev had investigated the conditions of vanishing for the Josephson tunneling and demonstrated the possibility of having normal electrodes in the junction. That is, no superconducting electrodes are necessary, and, therefore, coulomb blockade is possible to observe, in principle, even at room temperature. 

The most exciting property of these materials is that thin polycrystalline films can behave as two dimensional Josephson Tunnel Junction Arrays (110) displaying remarkably good electromagnetic coupling (111) both as emitters and receivers. Alternating current to direct current conversion has been observed in bulk samples (112), but the thin film geometry allows use of one film as a radiation emitter, and another film as the receiver (111). 

See also Josephson Tunnel-Junction and Thin Films. 

In 1962, B. Josephson recognized the implications of the complex order parameter for the dynamics of the superconductor, and in particular when one considers a system consisting of two bulk conductors connected by a weak link." This research led to tile development of a series of weak link devices commonly called Josephson junctions. See also Josephson Tunnel-Junction. These devices hold much promise for achieving ultra high-speed computers where switching time is of the order of 1CT11 second. 

The problem of lateral modification of HTSC surface layers, and the local electrosynthesis of HTSCs on the surface of patterned substrates including the precursors is very interesting. Such processes can occur, for example, during electrooxidation of metals when the process in its initial stages takes place only on isolated microscopic regions. Thus, Josephon junctions on the surface of Bi-Sn alloys [222] and on ceramic YBCO samples [295,444] were obtained by using electrochemical oxidation without any special local techniques. But it is hard to control such oxidation processes, and sufficient reproducibility cannot be ensured for most systems. Josephson tunnel junctions based on electrochemically synthesized BKBO crystals have been described [445]. 

It is now generally agreed, however, that the observed increase in results from suppression of charge density wave formation rather than some exotic quasi-two-dimensional mechanism. However, the effect of the two-dimensional anisotropy of the material is of considerable interest. It has been found that the critical field behavior is in broad agreement with theoretical predictions based on a model of a layered compound containing two-dimensional superconducting layers weakly coupled via Josephson tunneling. ... 

Jaklevic, J. C., Lambe, J., Silver, A. H. Mercereau, J. E. (1964). Quantum interference effects in Josephson tunneling. Physical Review Letters, 12,159-62. Jiles, D. (1991). Introduction to Magnetism and Magnetic Materials. Chapman and Hall, London, p. 388. 

Josephson tunneling across Y123/Pb junction in the nh-plane 598... 

Break junction. The sample is mechanically broken into two pieces, which are then brought close to each other so that a tunneling current is observed. In this geometry, both electrodes are the same superconductors, and hence Josephson tunneling is expected. 

Fig. 27. (a) Fraimhofar diffiaction pattern for the critical current vs magnetic flux threading the junction barrier that is characteristic of a single Josephson tunnel Junction, (b) Diffraction patterns expected for a single corner Junction with s-wave (isotropic or anisotropic) and dj,2 2 pairing symmetry. After Wollman et al. (1995, fig. 1). 

Superconducting Properties. By means of flux quantization and Josephson tunneling experiments, it has been firmly established that superconductivity in the cuprate corrqtounds is based on electron pairs similar to that of conventional Bardeen-Cooper-Schreiffer (BCS) superconductors. However, there are currently widely... 

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. 

Very large scale integration (VLSI) technology and electronic devices Carbides and diborides as field and thermal emitters, TiN as a diffusion barrier in metallization to Si semiconductors, resistive thermoconductive humidity sensors with TaN film, and Josephson tunnel junctions with NbN film. 

RF Broom, RB Laibowitz, TO Mohr, W Walter. Fabrication and properties of niobium Josephson tunnel junctions. IBMJ Res Dev 24 212, 1980. 

H Kroger, LN Smith, DW JiUie. Selective niobium anodication process for fabricating Josephson tunnel junctions. Appl Phys Lett 39 280, 1981. 

A Shoji, F Shinoki, S Kosaka, M Aoyagi, H Hayakawa. New fabrication process for Josephson tunnel junctions with (niobium nitride, niobium) double-layered electrodes. Appl Phys Lett 41 1097, 1982. 

M Gervitch, MA Washington, HA Huggins. High quality refractory Josephson tunnel junctions utilizing thin aluminum layers. Appl Phys Lett 42 472, 1983. 

F Shinoki, A Shoji, S Kosaka, H Hayakawa. Niobium nitride Josephson tunnel junctions with oxidized amorphous silicon barriers. Appl Phys Lett 38 285, 1981. 

A Shoji, M Aoyagi, S Kosaka. Temperature-dependent properties of niobium nitride Josephson tunnel junctions. IEEE Trans Magn 23 1464, 1987. 

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