Ballistic anisotropic magnetoresistance

TL;DR

This paper predicts and demonstrates ballistic anisotropic magnetoresistance (BAMR) in ferromagnetic nanowires, showing conductance changes with magnetization direction due to spin-orbit effects, supported by ab-initio calculations.

Contribution

It introduces the concept of BAMR in ballistic conductors and provides first-principles calculations showing its significance in Ni and Fe nanowires.

Findings

BAMR causes sizable conductance changes with magnetization orientation.

Spin-orbit interaction influences the electronic band structure.

Ab-initio calculations confirm the effect in Ni and Fe nanowires.

Abstract

Electronic transport in ferromagnetic ballistic conductors is predicted to exhibit ballistic anisotropic magnetoresistance (BAMR) - a change in the ballistic conductance with the direction of magnetization. This phenomenon originates from the effect of the spin-orbit interaction on the electronic band structure which leads to a change in the number of bands crossing the Fermi energy when the magnetization direction changes. We illustrate the significance of this phenomenon by performing ab-initio calculations of the ballistic conductance in ferromagnetic Ni and Fe nanowires which display a sizable BAMR when the magnetization changes direction from parallel to perpendicular to the wire axis.