Conductance of Ferro- and Antiferro-magnetic single-atom contacts: A first-principles study

TL;DR

This study uses first-principles calculations to analyze how spin configurations affect conductance in various single-atom magnetic junctions, revealing effects like spin valve behavior and spin filtering depending on the atomic composition and magnetic states.

Contribution

It provides a detailed first-principles analysis of spin-dependent conductance in single-atom magnetic junctions, highlighting how spin configurations influence electronic transport properties.

Findings

Spin-up conductance increases when switching from ferromagnetic to antiferromagnetic states.

A 22% variation in total conductance demonstrates a spin valve effect in Ni-Cu/Ni(001).

Spin configuration changes can enhance or suppress the spin filter effect depending on the junction.

Abstract

We present a first-principles study on the spin denpendent conductance of five single-atom magnetic junctions consisting of a magnetic tip and an adatom adsorbed on a magnetic surface, i.e., the Co-Co/Co(001) and Ni-X/Ni(001) (X=Fe, Co, Ni, Cu) junctions. When their spin configuration changes from ferromagnetism to anti-ferromagnetism, the spin-up conductance increases while the spin-down one decreases. For the junctions with a magnetic adatom, there is nearly no spin valve effect as the decreased spin-down conductance counteracts the increased spin-up one. For the junction with a nonmagnetic adatom (Ni-Cu/Ni(001)), a spin valve effect is obtained with a variation of 22% in the total conductance. In addition, the change in spin configuration enhances the spin filter effect for the Ni-Fe/Ni(001) junction but suppresses it for the other junctions.