Magnetic and orbital blocking in Ni nanocontacts

TL;DR

This study uses ab initio calculations to investigate the origin of magneto-resistance in nickel nanocontacts, concluding that domain wall scattering does not explain large MR, and emphasizing the importance of orbital electron nature.

Contribution

It provides a detailed ab initio analysis showing that large MR in Ni nanocontacts is not due to domain wall scattering, challenging previous assumptions.

Findings

Transport depends on orbital nature of electrons

Results agree with experimental conductance values

Domain wall scattering does not cause large MR

Abstract

We address the fundamental question of whether magneto-resistance (MR) of atomic-sized contacts of Nickel is very large because of the formation of a domain wall (DW) at the neck. Using {\em ab initio} transport calculations we find that, as in the case of non-magnetic electrodes, transport in Ni nanocontacts depends very much on the orbital nature of the electrons. Our results are in agreement with several experiments in the average value of the conductance. On the other hand, contrary to existing claims, DW scattering does {\em not} account for large MR in Ni nanocontacts.