Critical Current Oscillations of Josephson Junctions Containing PdFe Nanomagnets

Microscopic model of critical current noise in Josephson junctions.

We present a simple microscopic model to show how fluctuating two-level systems in a Josephson junction tunnel barrier of thickness L can modify the potential energy of the barrier and produce critical current noise spectra. We find low frequency 1/f noise that goes as L5. Our values are in good agreement with recent experimental measurements of critical current noise in Al/AlOx/Al Josephson ju...

Critical current calculations for long 0-π Josephson junctions

A zigzag boundary between a dx2−y2 and an s-wave superconductor is believed to behave like a long Josephson junction with alternating sections of 0 and π symmetry. We calculate the field-dependent critical current of such a junction, using a simple model. The calculation involves discretizing the partial differential equation for the phase difference across a long 0-π junction. In this form, th...

Critical current oscillations in strong ferromagnetic pi junctions.

We report magnetic and electrical measurements of Nb Josephson junctions with strongly ferromagnetic barriers of Co, Ni, and Ni80Fe20 (Py). All these materials show multiple oscillations of critical current with a barrier thickness implying repeated 0-pi phase transitions in the superconducting order parameter. We show, in particular, that the Co barrier devices can be accurately modeled using ...

Josephson junctions with tunable current-phase relation

A. Lipman,1 R. G. Mints,1 R. Kleiner,2 D. Koelle,2 and E. Goldobin2,* 1The Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel 2Physikalisches Institut and Center for Collective Quantum Phenomena in LISA+, Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany (Received 29 September 2014; revised manuscript received 22 Octob...

Spatial dependence of plasma oscillations in Josephson tunnel junctions.