Self-assembly of Nanometer-scale Magnetic Dots with Narrow Size Distributions on an Insulating Substrate

TL;DR

This study demonstrates the controlled self-assembly of nanometer-scale magnetic iron dots with narrow size distributions on NaCl(001), combining experimental techniques and mean-field theory to understand size tuning via strain interactions.

Contribution

It introduces a method to produce narrowly distributed magnetic nanodots on an insulator and explains the size selection mechanism through a phenomenological mean-field model.

Findings

Narrow size distribution of iron dots achieved without wetting layer.

Dot sizes can be tuned by iron dosage without broadening.

Size selection driven by strain-mediated dot-dot interactions.

Abstract

The self-assembly of iron dots on the insulating surface of NaCl(001) is investigated experimentally and theoretically. Under proper growth conditions, nanometer-scale magnetic iron dots with remarkably narrow size distributions can be achieved in the absence of a wetting layer Furthermore, both the vertical and lateral sizes of the dots can be tuned with the iron dosage without introducing apparent size broadening, even though the clustering is clearly in the strong coarsening regime. These observations are interpreted using a phenomenological mean-field theory, in which a coverage-dependent optimal dot size is selected by strain-mediated dot-dot interactions.