Effect of Twisting and Stretching on Magneto Resistance and Spin Filtration in CNTs

Anil Singh,Sudhanshu Choudhary

doi:10.3390/magnetochemistry3030027

Abstract

Spin-dependent quantum transport properties in twisted carbon nanotube and stretched carbon nanotube are calculated using density functional theory (DFT) and non-equilibrium green’s function (NEGF) formulation. Twisting and stretching have no effect on spin transport in CNTs at low bias voltages. However, at high bias voltages the effects are significant. Stretching restricts any spin-up current in antiparallel configuration (APC), which results in higher magneto resistance (MR). Twisting allows spin-up current almost equivalent to the pristine CNT case, resulting in lower MR. High spin filtration is observed in PC and APC for pristine, stretched and twisted structures at all applied voltages. In APC, at low voltages spin filtration in stretched CNT is higher than in pristine and twisted ones, with pristine giving a higher spin filtration than twisted CNT.

Highlights

Spintronics involves investigations associated with the electron’s spin, magnetic moment, and charge
The ferromagnetic material is chosen because of its unique electronic properties; that is, that spin-up and spin-down electrons pass from one electrode to other electrode through the magnetic junction with different Fermi energies
High tunnel magnetoresistance and high spin filtration are required for a Carbon nanotube (CNT)-based spintronic device to deliver better performance and ensure its use in spin valves and other spintronic-based devices

Summary

Introduction

Spintronics involves investigations associated with the electron’s spin, magnetic moment, and charge. A two probe magnetic junction is a three-layer device in which nonmagnetic material is sandwiched between two electrodes. The ferromagnetic material is chosen because of its unique electronic properties; that is, that spin-up and spin-down electrons pass from one electrode to other electrode through the magnetic junction with different Fermi energies.

Results

Conclusion