Non-volatile superconducting tunnelling magnetoresistance memory enabled by exchange-field gap engineering

TL;DR

This paper presents a superconducting tunnelling magnetoresistance device functioning as a non-volatile cryogenic memory, compatible with superconducting logic, operating below 4 K with low power dissipation.

Contribution

It introduces a novel exchange-field controlled superconducting memory device integrating a de Gennes spin valve with a tunnel junction, enabling scalable cryogenic memory arrays.

Findings

Operates at millivolt bias with nanowatt-level read power.

Functions across the full superconducting temperature range down to 0.25 K.

Exhibits robust quasiparticle tunnelling magnetoresistance.

Abstract

Scalable, low-dissipation memory operating below 4 K is a critical requirement for superconducting and quantum computing systems. Existing cryogenic memory technologies rely on CMOS derivatives or hybrid architectures that incur leakage, refresh overhead or limited compatibility with superconducting logic. Here we demonstrate a superconducting tunnelling magnetoresistance device that functions as a non-volatile cryogenic memory element across the full superconducting temperature range. By integrating a de Gennes spin valve with a superconducting tunnel junction in a current perpendicular-to-plane geometry, we realise exchange-field control of the superconducting energy gap. This produces two magnetically switchable gap voltages and robust quasiparticle tunnelling magnetoresistance down to 0.25 K.The device operates at millivolt bias with nanowatt-level read power and zero standby dissipation. Its vertical junction architecture and Nb-based materials platform enable compatibility with superconducting logic and scalable cryogenic memory arrays.