Influence of nonmagnetic impurities on the magnetic properties of tunnel superconducting junctions with a nonsinusoidal current-phase relation

Editorial Board PCSS Journal; O.M. Romanchuk; V.E. Sakhnyuk

doi:10.15330/pcss.27.2.366-371

Authors

O.M. Romanchuk Lesya Ukrainka Volyn National University, Lutsk, Ukraine
V.E. Sakhnyuk Lesya Ukrainka Volyn National University, Lutsk, Ukraine

DOI:

https://doi.org/10.15330/pcss.27.2.366-371

Keywords:

tunnel superconducting junction, current-phase relation, nonmagnetic impurities, magnetic properties, barrier transparency, oscillatory behavior

Abstract

We investigate the influence of nonmagnetic impurities and pair-breaking effects on the magnetic properties of tunnel superconducting junctions at temperatures close to the critical one. We show that as the transparency of the dielectric layer increases, the current-phase relation (CPR) strongly deviates from the classical sinusoidal form. An analytical expression for the magnetic field dependence of the critical current is derived, which is valid for an arbitrary impurity concentration. We analyze the role of the electron mean free path (impurity concentration) in the formation of the diffraction pattern. It is demonstrated that an increase in the barrier transparency and a change in the junction purity parameter lead to pronounced CPR anharmonicity. This anharmonicity results in a significant suppression of the side lobes in the magnetic diffraction pattern of the supercurrent. Asymptotic analysis confirms that in the limit of low barrier transparency, the diffraction pattern reduces to the classical Fraunhofer distribution.

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