Chemical and magnetic order in mass-selected large FeRh nanomagnets embedded in a carbon matrix

In this paper, we present some specific chemical and magnetic order results obtained on bimetallic FeRh nanoparticles prepared under non-equilibrium conditions using mass-selected Low Energy Cluster Beam Deposition. Clusters around 7 nm incident diameter are in situ sandwiched between amorphous carbon films before transfer air, with different surface coverage (from nearly isolated particles to percolating 2D films) artificially increase diameters of the (NPs) by coalescence. On such FeRh@C samples, observe NPs morphologies responses after UHV thermal treatments. By transmission electron microscopy (TEM), show that moderate annealing, nanoalloys evolved from a metastable structure towards equilibrium CsCl-type (B2) chemically ordered phase more spherical shape. While Superconducting Quantum Interference Device (SQUID) magnetometry measurements 700 °C-annealed clearly evidence huge magnetization enhancement for B2 robust ferromagnetic (FM) signature even at very low temperature unlike their bulk counterparts.