Electrical and Thermal Generation of Spin Currents by Magnetic Graphene

TL;DR

This paper demonstrates that magnetic graphene, when in proximity to an antiferromagnetic layer, can generate and control spin currents efficiently through electrical and thermal means, promising for ultra-thin spintronic devices.

Contribution

First experimental demonstration of large spin polarization in graphene due to proximity-induced magnetism, enabling efficient spin current generation and control in 2D materials.

Findings

Graphene exhibits approximately 14% spin polarization of conductivity.

Observation of spin-dependent Seebeck and anomalous Hall effects.

Spin transport in graphene is highly sensitive to the magnetization of adjacent layers.

Abstract

The demand for compact, high-speed and energy-saving circuitry urges higher efficiency of spintronic devices that can offer a viable alternative for the current electronics. The route towards this goal suggests implementing two-dimensional (2D) materials that provide large spin polarization of charge current together with the long-distance transfer of the spin information. Here, for the first time, we experimentally demonstrate a large spin polarization of the graphene conductivity ($\approx 14\%$) arising from a strong induced exchange interaction in proximity to a 2D layered antiferromagnetic. The strong coupling of charge and spin currents in graphene with high efficiency of spin current generation, comparable to that of metallic ferromagnets, together with the observation of spin-dependent Seebeck and anomalous Hall effects, all consistently confirm the magnetic nature of graphene. The high sensitivity of spin transport in graphene to the magnetization of the outermost layer of the adjacent interlayer antiferromagnet, also provides a tool to read out a single magnetic sub-lattice. The first time observations of the electrical and thermal generation of spin currents by magnetic graphene suggest it as the ultimate building block for ultra-thin magnetic memory and sensory devices, combining gate tunable spin-dependent conductivity, long-distance spin transport and spin-orbit coupling all in a single 2D material.