Josephson tunneling effect

Anderson, P. W., and Rowell, J. M. (1963) Probable observation of the Josephson superconducting tunneling effect. Phys. Rev. Lett. 10, 230. 

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. 

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. 

Superconductors exhibit a number of properties such as zero resistance, the Meissner effect, Josephson tunneling, the proximity effect, and persistent currents (12 ) that make them well suited for use in electronic devices and sensors. Accordingly, superconducting electronic devices are particularly attractive due to the ultra-low power dissipation and ultra-fast response times that can be achieved from such substances (13). 

Josephson B D 1962 Possible new effects in superconductive tunnelling Phys. Lett. 1 251... 

B. D. Josephson (Cambridge) theoretical predictions of the properties of a supercurrent through a tunnel barrier, in particular those phenomena which are generally known as the Josephson effects. 

The quantum of magnetic flux is only 2.07 x 10-15 Wb, which is approximately equal to the amount of the earth s magnetic field enclosed by a ring of 10p,m in diameter. The Josephson effect is observed when two superconductors are separated by a very thin insulating layer (about 20 nm). Single electrons and Cooper pairs can tunnel through such a layer. The characteristics of the Josephson junction are now used to define the volt and have enabled the uncertainty in the maintained standard to be reduced to 0.1 p,V. 

Since the Hamiltonian for atoms in accelerated optical lattices is similar to the Legett Hamiltonian for current-biased Josephson junctions [37], the present theory has been extended to describe effects of current modulations on the rate of macroscopic quanmm tunneling in Josephson junctions in Ref. [11]. 

In 1962 a postgraduate student, Brian Josephson, working in the University of Cambridge, and later to win a Nobel Prize, predicted that Cooper pairs should be able to tunnel through a thin (approximately 1 nm) insulating barrier from one superconductor to another with no electrical resistance [46]. This quantum tunnelling was confirmed by experiment and is known as the Josephson effect . The superconducting electronic devices exploit Josephson junctions. 

Josephson110 Effect. If two superconductors are separated by a thin layer (<3 nm for an insulator, several micrometers for a metal), then both a DC Josephson effect and an AC Josephson effect can occur. In the DC Josephson effect, a supercurrent can bridge the layer by quantum-mechanical tunneling, but there is a change in phase, which can be detected. It is very sensitive to magnetic fields indeed the supercurrent has the form f = f0 sin (O/O0)/ 7i(/0), where I0 depends on the temperature and the structure of the junction. If a DC potential V is applied across a Josephson junction, then the AC Josephson effect creates a response at a frequency... 

ZENO AND ANTI-ZENO EFFECTS IN DRIVEN JOSEPHSON JUNCTIONS CONTROL OF MACROSCOPIC QUANTUM TUNNELING... 

As a 22-year-old graduate student, Brian Josephson (1962) suggested that it should be possible for a current to pass between the two superconductors, even if there were no voltage difference between them. Although this behavior would be impossible classically, it could occur because of quantum mechanical tunneling of Cooper pairs across the junction. An observation of this Josephson effect was made by Anderson and Rowell in 1963. 

Josephson effect - The tunneling of electron pairs through a thin insulating layer which separates two superconductors. When a potential difference is applied to the superconductors, an alternating current is generated whose frequency is precisely proportional to the potential difference. This effect has important applications in metrology and determination of fundamental physical constants. 

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