Template-assisted self-assembly of individual and clusters of magnetic nanoparticles

Abstract

The deliberate control over the spatial arrangement of nanostructures is the desired goal for many applications such as, for example, in data storage, plasmonics or sensor arrays. Here we present a novel method to assist the self-assembly process of magnetic nanoparticles. The method makes use of nanostructured aluminum templates obtained after anodization of aluminum discs and the subsequent growth and removal of the newly formed alumina layer, resulting in a regular honeycomb-type array of hexagonally shaped valleys. The iron oxide nanoparticles, 20 nm in diameter, are spin-coated onto the surface of honeycomb nanostructured Al templates. Depending on the size, each hexagon site can host up to 30 nanoparticles. These nanoparticles form clusters of different arrangements within the valleys, such as collars, chains and hexagonally closed islands. Ultimately, it is possible to isolate individual nanoparticles. The strengths of the magnetic interaction between particles in a cluster are probed using the memory effect known from the coupled state in superspin glass systems.

Nanoporous Anodic Alumina Platforms: Engineered Surface Chemistry and Structure for Optical Sensing Applications

“…The magnetic nanoparticles were found to form clusters of different arrangements within the valleys of pretextured Al, such as collars, chains and hexagonally closed islands. They used memory effect to probe the strength of magnetic interactions between particles [120]. …”

Template Assisted Deposition of Ferromagnetic Nanostructures: from Antidot Thin Films to Multisegmented Nanowires

“…The development by Masuda and Fukuda of the two step anodization process for the fabrication of highly ordered nanoporous anodic aluminum oxide (AAO) templates [4] paved the way for the template-assisted deposition of a wide variety of nanomaterials. These nanomaterial families range from nanowire [5,6] and nanotube arrays [7] nanoparticle clusters [8] and antidot thin films [9,10], among others. The highly self-ordered hexagonal symmetry of the pores arrangement exhibited by the AAO templates displays narrow pore size distributions having well-defined interpore distances.…”

Effective demagnetizing tensors in arrays of magnetic nanopillars

“…The study of this second effect in a controlled environment is the objective of the present paper. Solid close-packed assemblies are optimal environments because of the accurate experimental control of the two involved geometric features, namely, the particle morphology and the particles ordering arrangement [4]. The anodic aluminum oxide, extensively used for nanowires production, provides a good patterned template to design these assemblies [5][6][7].…”