Evidence of the inverse proximity effect in tunnel magnetic Josephson Junctions

TL;DR

This paper investigates the inverse proximity effect in tunnel magnetic Josephson junctions, revealing its significance for designing hybrid superconducting quantum devices operating below 4 K.

Contribution

It provides a comparative analysis of magnetic behavior in tunnel MJJs with different ferromagnetic layers, highlighting the role of temperature and interface transparency.

Findings

Inverse proximity effect influences magnetic properties of MJJs

Temperature and interface transparency are crucial factors

IPE must be considered in quantum device design

Abstract

Magnetic Josephson Junctions (MJJs) are a special class of hybrid systems where antagonistic correlations coexist, thus providing a key for advances in weak superconductivity, superconducting spintronics and quantum computation. So far, the memory properties of MJJs have been mostly investigated in view of digital electronics and for spintronic devices at liquid-helium temperature. At the operating temperature of quantum circuits, a magnetic order can rise in a Superconductor (S) at the S/Ferromagnet (F) interface, i.e., the inverse proximity effect (IPE), thus leading to a significant modification of the magnetic field patterns in MJJs. In this work, we have carried out a comparative investigation of the magnetic behavior of tunnel MJJs with a strong ferromagnetic layer inserted in the layout of both Nb and Al JJs, respectively. The comparative analysis validates the crucial role of the temperature, the fundamental scaling energies of S/F coupling systems, and the transparency of the S/F interface. This investigation points out that the IPE is a key aspect to consider when designing tunnel MJJs operating well below 4 K and thus in the perspective of hybrid superconducting quantum architectures.