Layering of magnetic nanoparticles at amorphous magnetic templates with perpendicular anisotropy

TL;DR

This study demonstrates the self-assembly of monodisperse magnetite nanoparticles onto an amorphous magnetic template with perpendicular anisotropy, revealing stable layered structures influenced by particle magnetic moments.

Contribution

It introduces a method for assembling magnetic nanoparticles into stable layers on amorphous magnetic templates with out-of-plane anisotropy.

Findings

Nanoparticles form stable, layered structures on magnetic templates.

Layer density correlates with the particles' remanent magnetic moment.

Self-assembly is robust against cleaning and rinsing.

Abstract

We reveal the assembly of monodisperse magnetite nanoparticles of sizes 5 nm, 15 nm and 25 nm from dilute water-based ferrofluids onto an amorphous magnetic template with out-of-plane anisotropy. From neutron reflectometry experiments we extract density profiles and show that the particles self-assemble into layers at the magnetic surface. The layers are extremely stable against cleaning and rinsing of the substrate. The density of the layers is determined by and increases with the remanent magnetic moment of the particles.