Finite size effects on the metamagnetic phase transition in a thick B2 FeRh nanocluster film.

FeRh alloys in the CsCl-type (B2) chemically ordered phase present an antiferromagnetic to ferromagnetic order transition around 370 K observed in bulk and continuous films but absent in nanoclusters. In this study, we investigate the thermal magnetic behavior of a thick film composed of assembled FeRh nanoclusters preformed in the gas phase. This work reveals a broad and asymmetric metamagnetic transition with a consequent residual magnetization at low temperature.

Self-Assembled Permanent Micro-Magnets in a Polymer-Based Microfluidic Device for Magnetic Cell Sorting.

Magnetophoresis-based microfluidic devices offer simple and reliable manipulation of micro-scale objects and provide a large panel of applications, from selective trapping to high-throughput sorting. However, the fabrication and integration of micro-scale magnets in microsystems involve complex and expensive processes. Here we report on an inexpensive and easy-to-handle fabrication process of micrometer-scale permanent magnets, based on the self-organization of NdFeB particles in a polymer matrix (polydimethylsiloxane, PDMS).

Elaboration of Nanomagnet Arrays: Organization and Magnetic Properties of Mass-Selected FePt Nanoparticles Deposited on Epitaxially Grown Graphene on Ir(111).

The moiré pattern created by the epitaxy of a graphene sheet on an iridium substrate can be used as a template for the growth of 2D atomic or cluster arrays. We observed for the first time a coherent organization of hard magnetic preformed FePt nanoparticles on the 2D lattice of graphene on Ir(111). Nanoparticles of 2 nm diameter have been mass selected in a gas phase and deposited with low energy on the hexagonal moiré pattern.

Cubic chemically ordered FeRh and FeCo nanomagnets prepared by mass-selected low-energy cluster-beam deposition: a comparative study.

Near the point of equiatomic composition, both FeRh and FeCo bulk alloys exhibit a CsCl-type (B2) chemically ordered phase that is related to specific magnetic properties, namely a metamagnetic anti-ferromagnetic/ferromagnetic transition near room temperature for FeRh and a huge magnetic moment for the FeCo soft alloy. In this paper, we present the magnetic and structural properties of nanoparticles of less than 5 nm diameter embedded in an inert carbon matrix prepared by mass-selected low-energy cluster-beam deposition technique. We obtained a CsCl-type (B2) chemically ordered phase for annealed nanoalloys.

Moiré induced organization of size-selected Pt clusters soft landed on epitaxial graphene.

Two-dimensional hexagonal arrays of Pt nanoparticles (1.5 nm diameter) have been obtained by deposition of preformed and size selected Pt nanoparticles on graphene. This original self-organization is induced, at room temperature, by the 2D periodic undulation (the moiré pattern) of graphene epitaxially grown on the Ir(111) surface.