Current assisted memory effect in superconductor-ferromagnet bilayers : a potential candidate for memristors

Abstract

Superconductivity and ferromagnetism are two very useful phenomena, hoewever they rarely coexist in bulk materials. Bringing them together in an artificial hybrid bilayer produces some unusual results. We designed and studied a system of superconductor-ferromagnet bilayer with a thin insulating buffer layer between them. Such a superconductor-ferromagnet bilayer with magnetostatic coupling is proposed for use as a multibit superconductor memory device and a potential candidate as a memristor. Numerical simulations were performed by using Ginzburg–Landau and Landau–Lifshitz-Gilbert models for superconductor and ferromagnet materials, which highlighted some interesting resistive memory effects in the superconducting layer in the bilayer system. A vortex pattern in the superconductor was observed to be strongly coupled with the ferromagnet domain structure, while their dynamics were controlled by the current flowing through the superconductor. Carrier concentration, energy components and magnetization in the superconducting layer were studied as a function of applied current pulses in the superconductor layer, indicating the information storage of the current pulses. Multiple resistive states were observed, pointing towards the possibility that such a device could be used as a multibit data storage device.