High-Quality Ferromagnetic Josephson Junctions Based on Aluminum Electrodes

Abstract

Aluminum Josephson junctions are the building blocks for the realization of superconducting quantum bits. Attention has been also paid to hybrid ferromagnetic Josephson junctions, which allow switching between different magnetic states, making them interesting for applications such as cryogenic memories, single-photon detectors, and spintronics. In this paper, we report on the fabrication and characterization of high-quality ferromagnetic Josephson junctions based on aluminum technology. We employed an innovative fabrication process inspired by niobium-based technology, allowing us to obtain very high-quality hybrid aluminum Josephson junctions; thus, supporting the use of ferromagnetic Josephson junctions in advanced quantum circuits. The fabrication process is described in detail and the main DC transport properties at low temperatures (current–voltage characteristic, critical current as a function of the temperature, and the external magnetic field) are reported. Here, we illustrate in detail the fabrication process, as well as the main DC transport properties at low temperatures (current–voltage characteristic, critical current as a function of the temperature, and the external magnetic field).

Highly Sensitive Tunable Magnetometer Based on Superconducting Quantum Interference Device

“…The similar procedure is described in detail in ref. [ 35 ]. In the first step, on a silicon wafer provided for the thermal oxide surface layer, the base structure to house the Josephson junctions is patterned by standard optical photolithography on an image reversal resist for high resolution (AZ ® 5214E—MicroChemicals GmbH, Ulm, Germany).…”

Superconductivity in Nanosystems: A Fruitful Path to New Phenomenology in Quantum Materials

“…Also, Vettoliere et al [ 7 ] focused their attention on the case of Josephson tunnel nanojunctions, whereto a ferromagnetic element is added. They report the fabrication of such systems using multistage deposition–lithography processes.…”

“…They report the fabrication of such systems using multistage deposition–lithography processes. The so-obtained junctions become switchable using the influence of the magnetic element over the superconducting wave function, which may be of great relevance in the area of the emerging quantum computing and communications technologies [ 5 , 7 ]. The junctions are Al-based and bear good prospects of integrability in different types of quantum circuits.…”