YBa2Cu3O7/LaXMnO3 (X: Ca, Sr) based Superconductor/Ferromagnet/Superconductor junctions with memory functionality

TL;DR

This paper reports the fabrication and experimental study of nano-scale superconductor/ferromagnet/superconductor junctions using high-Tc cuprate superconductors and colossal magnetoresistive manganites, demonstrating their potential as memory devices with high-temperature operation.

Contribution

It introduces a novel single-layer CMR ferromagnetic junction that enables memory functionality in both superconducting and normal states, operating up to room temperature.

Findings

Magnetization switches abruptly in a mono-domain manner.

The junction exhibits hysteretic magnetoresistance due to CMR.

Memory read-out is achieved via resistance measurement in a magnetic field.

Abstract

Complex oxides exhibit a variety of unusual physical properties, which can be used for designing novel electronic devices. Here we fabricate and study experimentally nano-scale Superconductor/ Ferromagnet/Superconductor junctions with the high-Tc cuprate superconductor YBa2Cu3O7 and the colossal magnetoresistive (CMR) manganite ferromagnets LaXMnO3 (X: Ca or Sr). We demonstrate that in a broad temperature range the magnetization of a manganite nanoparticle, forming the junction interface, switches abruptly in a mono-domain manner. The CMR phenomenon translates the magnetization loop into a hysteretic magnetoresistance loop. The latter facilitates a memory functionality of such a junction with just a single CMR ferromagnetic layer. The orientation of the magnetization (stored information) can be read out by simply measuring the junction resistance in an applied magnetic field. The CMR facilitates a large read-out signal in a small applied field. We argue that such a simple single layer CMR junction can operate as a memory cell both in the superconducting state at cryogenic temperatures and in the normal state up to room temperature.

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