Mesoscopic superconducting memory based on bistable magnetic textures

TL;DR

This paper introduces a novel non-volatile superconducting memory device based on a mesoscopic ferromagnet's bistable magnetic textures, enabling fast, low-power, and reliable data storage through magnetic state control and critical current measurement.

Contribution

It demonstrates a new Josephson junction memory utilizing bistable magnetic textures in a mesoscopic ferromagnet, combining micromagnetic simulations with superconducting device design.

Findings

Distinct critical currents for different magnetic states enable reliable readout.

Micromagnetic simulations accurately predict stray fields affecting the superconducting interference pattern.

The device design offers a promising route for superconducting memory applications.

Abstract

With the ever-increasing energy need to process big data, the realization of low-power computing technologies, such as superconducting logic and memories, has become a pressing issue. Developing fast and non-volatile superconducting memory elements, however, remains a challenge. Superconductor-ferromagnet hybrid devices offer a promising solution, as they combine ultra-fast manipulation of spins with dissipationless readout. Here, we present a new type of non-volatile Josephson junction memory that utilizes the bistable magnetic texture of a single mesoscopic ferromagnet. We use micromagnetic simulations to design an ellipse-shaped planar junction structured from a Nb/Co bilayer. The ellipse can be prepared as uniformly magnetized or as a pair of vortices at zero applied field. The two states yield considerably different critical currents, enabling reliable electrical readout of the element. We describe the mechanism used to control the critical current by applying numerical calculations to quantify the local stray field from the ferromagnet, which shifts the superconducting interference pattern. By combining micromagnetic modeling with bistable spin-textured junctions, our approach presents a novel route towards realizing superconducting memory applications.