Critical current diffraction pattern of SIFS Josephson junctions with step-like F-layer

TL;DR

This paper investigates the diffraction pattern of critical currents in SIFS Josephson junctions with a step-like ferromagnetic layer, analyzing how different layer thicknesses affect magnetic and electrical properties.

Contribution

It introduces a model that accurately describes the critical current dependence on magnetic field by considering varying critical current densities and magnetization in the ferromagnetic layer.

Findings

Critical current patterns depend on F-layer thickness variations.

The model fits experimental data well.

Magnetization effects influence the diffraction pattern.

Abstract

We present the latest generation of superconductor-insulator-ferromagnet-superconductor Josephson tunnel junctions with a step-like thickness of the ferromagnetic (F) layer. The F-layer thicknesses $d_1$ and $d_2$ in both halves were varied to obtain different combinations of positive and negative critical current densities $j_{c,1}$ and $j_{c,2}$. The measured dependences of the critical current on applied magnetic field can be well described by a model which takes into account different critical current densities (obtained from reference junctions) and different net magnetization of the multidomain ferromagnetic layer in both halves.