Thermal fluctuation effects far from the critical temperature
Thesis/Dissertation
·
OSTI ID:5974468
We report the first measurements of thermal fluctuations in superconductors at temperatures far from the critical temperature T/sub c/ (T approx. 1/2 T/sub c/), and also the first measurements that use thermal fluctuations to probe the non-equilibrium dynamics of a superconductor. This is the first work that separately measures the fluctuations that cause a superconductor to switch to the dissipative state and those that cause it to switch back to the superconductor state. These unique measurements allowed: (1) The first measurement experimental confirmation of the theory of Langer, Ambegaokar, McCumber, and Halperin (LAMH) where T/sub c/ was not an adjustable parameter. This rigorous test of the theory was not previously possible because earlier measurements were carried out very near T/sub c/, where a change of many orders of magnitude of predicted effects occur if the assumed T/sub c/ changes a few millidegrees. Thus T/sub c/ in all previous work was always adjusted so as to get agreement with the theory. (2) The first verification of the LAMH model far from T/sub c/. (3) The first experimental confirmation of the relation between current and transition probability that was predicted in the LAMH model. (4) Confirmation that the Lamda model developed by Peters, Wolf, and Rachford (PWR) to explain the dynamics on the nonequilibrium region can be extended to explain fluctuation effects. This is based on an original phenomenological extension of the LAMH model that is developed in this work and on our data. (5) The most direct measurement to date of the nature of the decay of the dissipative region in a weak link. These measurements show that the region recovers exponentially in time as proposed in the Lamda model.
- Research Organization:
- Catholic Univ. of America, Washington, DC
- OSTI ID:
- 5974468
- Country of Publication:
- United States
- Language:
- English
Similar Records
Intrinsic dissipative fluctuation rate in mesoscopic superconducting rings
Fluctuations and the determination of critical currents in granular microbridges
Intrinsic resistivity and the SO(5) theory of high-temperature superconductors
Journal Article
·
Fri Dec 31 23:00:00 EST 1993
· Physical Review, B: Condensed Matter; (United States)
·
OSTI ID:5404073
Fluctuations and the determination of critical currents in granular microbridges
Conference
·
Fri Dec 14 23:00:00 EST 1979
· AIP Conf. Proc.; (United States)
·
OSTI ID:5472145
Intrinsic resistivity and the SO(5) theory of high-temperature superconductors
Journal Article
·
Tue Mar 31 23:00:00 EST 1998
· Physical Review, B: Condensed Matter
·
OSTI ID:627560