Observation of Huge Magnetoresistance and Multiferroic-like Behavior of Co Nanoparticles in a C60 matrix

TL;DR

This paper reports a record-high tunneling magnetoresistance ratio of 1,400,000% in a C60-Co nanocomposite, driven by Coulomb blockade and magnetic switching effects, with implications for advanced spintronic devices.

Contribution

It introduces a giant TMR effect in a C60-Co nanocomposite, combining Coulomb blockade and multiferroic-like control of magnetization and charge states.

Findings

Achieved a TMR ratio of 1,400,000% at room temperature.

Demonstrated control of magnetization and charge states via electric and magnetic fields.

Revealed a new physics mechanism involving Coulomb blockade and multiferroic-like behavior.

Abstract

Tunneling magnetoresistance (TMR) via oxides or molecules includes fruitful physics, such as spin filtering and hybridized interface states, in addition to various practical applications using large TMR ratio at room temperature. Then, a larger TMR effect with a new fundamental physics is awaited because further progress on spintronics can be realized. Here we report a discovery of a gigantic TMR ratio of 1,400,000% in a C60-Co nanocomposite spin device. The observed effect is induced by a combination of a Coulomb blockade effect and a novel magnetic switching effect. Theoretical investigation reveals that an electric field and a magnetic field control the magnetization and the electronic charging state, respectively, of the Co nanoparticles as in physics of multiferroicity.