In the realm of superconducting electronics, magnetic Josephson junctions are preferred for memory applications. Most demonstrated devices for this purpose use diffusive ferromagnets, resulting in a reduced I_cR_n product; or a combination of ferromagnet with an insulating layer like AlOx in the form of an SIFS junction, thus achieving reasonable I_cR_n products at the cost of a more complex multi-layer growth process. In this presentation, I will demonstrate a simple tri-layer Josephson memory device using ferromagnetic insulating GdN-based S/FI/S vertical mesa-type junctions, with reliable non-volatile memory operation without the need of a shunt resistor at 4.2 K with characteristic voltages close to 0.2mV[1]. The use of the ferromagnetic insulator layer, results in a straightforward thin film growth and fabrication process which is almost identical to that used for Nb/AlOx/Nb junctions thus probably paving the way for integration of these devices in Rapid Single Flux Quantum circuits.

[1] P. K. Sharma and A. Pal, ‘Shunt-free cryogenic memory using ferromagnetic insulator-based Josephson junctions’, Appl Phys Lett, vol. 125, no. 5, Jul. 2024, doi: 10.1063/5.0211466.