Ferromagnetic Josephson switching device with high characteristic voltage

TL;DR

This paper introduces a fast, scalable magnetic Josephson junction device with high characteristic voltage, suitable for high-speed cryogenic memory and compatible with existing superconducting SFQ circuits.

Contribution

The development and experimental validation of a superconducting ferromagnetic Josephson device with high IcRn, demonstrating its potential for integration into ultra-fast superconducting digital circuits.

Findings

IcRn > 700 μV in SIFS MJJs

Device switching via magnetic field pulses

IcRn only ~30% lower than conventional junctions

Abstract

We develop a fast Magnetic Josephson Junction (MJJ) - a superconducting ferromagnetic device for a scalable high-density cryogenic memory compatible in speed and fabrication with energy-efficient Single Flux Quantum (SFQ) circuits. We present experimental results for Superconductor-Insulator-Ferromagnet-Superconductor (SIFS) MJJs with high characteristic voltage IcRn of >700 uV proving their applicability for superconducting circuits. By applying magnetic field pulses, the device can be switched between MJJ logic states. The MJJ IcRn product is only ~30% lower than that of conventional junction co-produced in the same process, allowing for integration of MJJ-based and SIS-based ultra-fast digital SFQ circuits operating at tens of gigahertz.