Low Temperature Physics: 39, 294 (2013); https://doi.org/10.1063/1.4795203 (5 pages)
Физика Низких Температур: Том 39, Выпуск 3 (Март 2013), c. 378-383    ( к оглавлению , назад )

Macroscopic quantum tunneling and retrapping processes in moderately damped YBaCuO Josephson junctions

D. Massarotti1,2, L. Longobardi3,2, L. Galletti1,2, D. Stornaiuolo1,2, G. Rotoli3, and F. Tafuri3,2,1

1Dip. Scienze Fisiche, Universitá di Napoli Federico II, Monte S. Angelo via Cinthia, Napoli 80126, Italy
E-mail: dmassarotti@na.infn.it

2CNR-SPIN, UOS Napoli, Monte S. Angelo via Cinthia, Napoli 80126, Italy

3Dip. Ingegneria dell'Informazione, Seconda Universitá di Napoli, via Roma 29, Aversa (CE) 81031, Italy

Received November 1, 2012

Аннотация

The moderately damped regime in a Josephson junction (JJ) is quite common in devices characterized by low critical currents and therefore by low Josephson energies. Measurements of switching current distribution (SCD) are a direct way of discriminating the phase dynamics also in the nontrivial case of moderate damping, which is going to be more and more common with advances in nano-patterning superconductors and in materials science finalized to build hybrid systems. We report on measurements of SCDs, both in thermal and quantum regime, on moderately damped YBaCuO grain boundary biepitaxial JJs. A direct transition from phase diffusion regime to macroscopic quantum tunnelling occurs at about 130 mK. The crossover to the quantum regime is tuned by the magnetic field and phase dynamics is described by a fully consistent set of junction parameters derived through numerical simulations.

PACS: 74.72.–h Cuprate superconductors;
PACS: 85.25.Cp Josephson devices;
PACS: 74.50.+r Tunneling phenomena; Josephson effects.

Ключевые слова: phase dynamics, moderately damped regime, phase diffusion.