Hillion, A.Cavallin, A.Vlaic, S.Tamion, A.Tournus, F.Khadra, G.Dreiser, J.Piamonteze, C.Nolting, F.Rusponi, S.Sato, K.Konno, T. J.Proux, O.Dupuis, V.Brune, H.2013-03-052013-03-052013-03-05201310.1103/PhysRevLett.110.087207https://infoscience.epfl.ch/handle/20.500.14299/90103WOS:000315284800020In sharp contrast to previous studies on FeRh bulk, thin films, and nanoparticles, we report the persistence of ferromagnetic order down to 3 K for size-selected 3.3 nm diameter nanocrystals embedded into an amorphous carbon matrix. The annealed nanoparticles have a B2 structure with alternating atomic Fe and Rh layers. X-ray magnetic dichroism and superconducting quantum interference device measurements demonstrate ferromagnetic alignment of the Fe and Rh magnetic moments of 3 and 1 mu(B), respectively. The ferromagnetic order is ascribed to the finite-size induced structural relaxation observed in extended x-ray absorption spectroscopy. DOI: 10.1103/PhysRevLett.110.087207text::journal::journal article::research article