Repository: Freie Universit├Ąt Berlin, Math Department

Thermally active nanoparticle clusters enslaved by engineered domain wall traps

Tierno, Pietro and Johansen, Tom H. and Straube, Arthur V. (2021) Thermally active nanoparticle clusters enslaved by engineered domain wall traps. NATURE COMMUNICATIONS, 12 (5813). pp. 1-11.

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The stable assembly of fluctuating nanoparticle clusters on a surface represents a techno- logical challenge of widespread interest for both fundamental and applied research. Here we demonstrate a technique to stably confine in two dimensions clusters of interacting nano- particles via size-tunable, virtual magnetic traps. We use cylindrical Bloch walls arranged to form a triangular lattice of ferromagnetic domains within an epitaxially grown ferrite garnet film. At each domain, the magnetic stray field generates an effective harmonic potential with a field tunable stiffness. The experiments are combined with theory to show that the mag- netic confinement is effectively harmonic and pairwise interactions are of dipolar nature, leading to central, strictly repulsive forces. For clusters of magnetic nanoparticles, the sta- tionary collective states arise from the competition between repulsion, confinement and the tendency to fill the central potential well. Using a numerical simulation model as a quanti- tative map between the experiments and theory we explore the field-induced crystallization process for larger clusters and unveil the existence of three different dynamical regimes. The present method provides a model platform for investigations of the collective phenomena emerging when strongly confined nanoparticle clusters are forced to move in an idealized, harmonic-like potential.

Item Type:Article
Subjects:Mathematical and Computer Sciences > Mathematics > Applied Mathematics
Divisions:Department of Mathematics and Computer Science > Institute of Mathematics
ID Code:2629
Deposited By: Monika Drueck
Deposited On:21 Oct 2021 14:41
Last Modified:21 Oct 2021 14:41

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