First-principles calculation of exchange interaction and exchange force between magnetic Fe films

TL;DR

This study uses first-principles calculations to quantify the exchange interaction and force between magnetic Fe films, indicating potential for exchange force microscopy due to force magnitudes surpassing current detection limits.

Contribution

It provides the first quantitative estimates of exchange forces between Fe thin films using ab initio methods, highlighting their detectability with existing microscopy techniques.

Findings

Exchange force magnitude is around 10^{-9} N at d/a < 1.

Force decreases to about 10^{-10} N for 1 < d/a < 1.5.

Forces are detectable with current atomic force microscopy.

Abstract

First-principles calculations have been performed for the exchange interaction and exchange force between two magnetic Fe(100) thin films. It is shown that the magnitude of the calculated exchange force is of the order of $10^{-9} $N at $d/a < 1$ and of the order of $10^{-10} $N at $1 < d/a < 1.5$, where $d$ denotes the distance between surfaces of the two thin films and $a$ the lattice constant of bulk Fe. The obtained forces are sufficiently larger than the sensitivity of the current atomic force microscopy of $10^{-12} - 10^{-13}$N, which suggests the feasibility of the exchange force microscopy.