Related Experiment Video
Updated: May 15, 2026

Stable Aqueous Suspensions of Manganese Ferrite Clusters with Tunable Nanoscale Dimension and Composition
Published on: February 5, 2022
Spacing-dependent dipolar interactions in dendronized magnetic iron oxide nanoparticle 2D arrays and powders
Solenne Fleutot1, Gareth L Nealon, Matthias Pauly
1Institut de Physique et de Chimie des Matériaux de Strasbourg, UMR CNRS-UdS 7504, 23, rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France.
Abstract:
Self-assembly of nanoparticles (NPs) into tailored structures is a promising strategy for the production and design of materials with new functions. In this work, 2D arrays of iron oxide NPs with interparticle distances tuned by grafting fatty acids and dendritic molecules at the NPs surface have been obtained over large areas with high density using the Langmuir-Blodgett technique. The anchoring agent of molecules and the Janus structure of NPs are shown to be key parameters driving the deposition. Finally the influence of interparticle distance on the collective magnetic properties in powders and in monolayers is clearly demonstrated by DC and AC SQUID measurements. The blocking temperature T(B) increases as the interparticle distance decreases, which is consistent with the fact that dipolar interactions are responsible for this increase. Dipolar interactions are found to be stronger for particles assembled in thin films compared to powdered samples and may be described by using the Vogel Fulcher model.
Related Concept Videos
Diamagnetism
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets.
Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
Ferromagnetism
Valence Bond Theory
Van der Waals Interactions
π Electron Effects on Chemical Shift: Overview

