Non-Fraunhofer patterns of the anharmonic Josephson current influenced by strong interfacial pair breaking

Abstract

In the junctions with a strong Josephson coupling and a pronounced interfacial pair breaking, the magnetic interference patterns of the Josephson current are shown to differ substantially from the standard Fraunhofer shape. The Fraunhofer pattern occurs, when Josephson couplings are weak. The narrow peak of the critical current, centered at the zero magnetic field, and the suppressed hills at finite field values are the characteristic features of the non-Fraunhofer magnetic field modulation of the critical current, obtained in this paper.

Magnetic penetration depth and vortex structure in anharmonic superconducting junctions with an interfacial pair breaking

“…As was noted above, these are the narrow peaks in the current-phase relation of strongly anharmonic junctions, which transform into spatial peaks of the supercurrent density due to a spatial dependence of the phase difference. An effect of similar origin, but with a transformation into the magnetic flux dependence, has been recently predicted in strongly anharmonic junctions, whose widths are much less than the junction penetration depth [20]. The narrow central Fraunhofer peak of the total critical current was found to possess the following half-width at the half of the peak ( / 0 ) ≈ 1.35g δ /g 1, under the conditions g g δ and g 2 δ 1.…”

“…An effect of similar origin, but with a transformation into the magnetic flux dependence, has been recently predicted in strongly anharmonic junctions, whose widths are much less than the junction penetration depth. 20 The narrow central Fraunhofer peak of the total critical current was found to possess the following half width at the half of the peak (∆Φ Φ 0 ) ≈ 1.35g δ g ℓ ≪ 1, under the conditions g ℓ ≫ g δ and g 2 δ ≫ 1.…”

Boundary conditions for the order parameter and the proximity influenced internal phase differences in double superconducting junctions

“…The boundary conditions (6) have been used for describing single and double Josephson junctions within the GL theory [20,40,[72][73][74][75][76][77].…”

“…The estimate g ℓ ∼ Dξ(T )(l −1 imp + ξ −1 0 ), that sometimes is identified as the effective transparency [95,96], applies not only to junctions in the tunneling limit g ℓ ≪ 1 but also to those with moderate transparency not too close to unity. As the ratio ξ(T )/l in dirty superconductors can be ∼ 100 even at low temperatures, the quantity g ℓ ∼ Dξ(T )/l can vary, for small and moderate transparencies, from vanishingly small values in the tunneling limit to those well exceeding 100 near T c , when a pronounced anharmonic behavior of the Josephson current is known to take place [72,74,76,97]. In highly transparent junctions, for which 1 − D ≪ 1, the parameter g ℓ ∝ (1 − D) −1 can be very large, as follows from microscopic results for the Josephson current in planar junctions with thin interlayers [55,[92][93][94]97] (see also [26,98]).…”

Dynamical regimes of kinematic vortices in the resistive state of a mesoscopic superconducting bridge

“…Regarding JJs, several works have studied the influence of different materials in the Josephson vortex dynamics and the electrical properties of superconducting devices. For example, the Ginzburg-Landau formalism was also applied in the study of anharmonic currents in JJs [19,20]. In references [21,22], the authors theoretically and experimentally analyzed the influence of tailored JJs on the superconducting properties of annular samples.…”