Magneto-transport in impurity-doped few-layer graphene spin valve

TL;DR

This paper investigates spin-dependent electron transport in impurity-doped few-layer graphene spin valves, revealing how magnetic configurations and temperature influence conductance peaks and tunneling magnetoresistance, with implications for spintronic devices.

Contribution

It introduces a theoretical analysis of impurity effects on spin transport in graphene spin valves using nonequilibrium Green's functions, highlighting the impact of electrode magnetization orientation.

Findings

Resonant peaks in conductance depend on electrode magnetization alignment.

TMR can change sign with small variations in polarization.

Temperature affects conductance and TMR behavior.

Abstract

Using Keldysh nonequilibrium Green's function method we study the spin-dependent transport through impurity-doped few layer graphene sandwiched between two magnetic leads with an arbitrary mutual orientations of the magnetizations. We find for parallel electrodes magnetizations that the differential conductance possesses two resonant peaks as the applied bias increases. These peaks are traced back to a buildup of a magnetic moment on the impurity due to the electrodes spin polarization. For a large mutual angle of the electrodes magnetization directions, the two resonant peaks approach each others and merge into a single peak for antiparallel orientation of the electrodes magnetizations. We point out that the tunneling magnetoresistance (TMR) may change sign for relatively small changes in the values of the polarization parameters. Furthermore, we inspect the behaviour of the differential conductance and TMR upon varying the temperature.