Magnetoresistance Effect in Spin-Polarized Junctions of Ferromagnetically Contacting Multiple Conductive Paths: Applications to Atomic Wires and Carbon Nanotubes

TL;DR

This paper theoretically investigates how multiple conductive paths in ferromagnetic junctions influence spin-dependent transport and magnetoresistance, revealing that increasing paths enhances MR ratio, especially in carbon nanotubes.

Contribution

It introduces a theoretical analysis of spin transport in multi-path ferromagnetic junctions, highlighting the impact of path number and type on magnetoresistance enhancement.

Findings

MR ratio increases with the number of paths due to wave interference.

Carbon nanotubes exhibit larger MR ratios than atomic wires at the same number of paths.

Wave interference effects are key to understanding MR behavior in multi-path junctions.

Abstract

For spin-polarized junctions of ferromagnetically contacting multiple conductive paths, such as ferromagnet (FM)/atomic wires/FM and FM/carbon nanotubes/FM junctions, we theoretically investigate spin-dependent transport to elucidate the intrinsic relation between the number of paths and conduction, and to enhance the magnetoresistance (MR) ratio. When many paths are randomly located between the two FMs, electronic wave interference between the FMs appears, and then the MR ratio increases with increasing number of paths. Furthermore, at each number of paths, the MR ratio for carbon nanotubes becomes larger than that for atomic wires, reflecting the characteristic shape of points in contact with the FM.