Synthesis and magnetic properties of self-assembled FeRh nanoparticles

We report here the synthesis and magnetization behavior of tunable FeRh magnetic nanoparticles with both controllable composition and size. Fe(x)Rh(1-x) (x=0.35,0.44,0.51) nanoparticles of 4-20 nm size range were fabricated using a polyol coreduction process. The stoichiometry of Fe(x)Rh(1-x) nanoparticles was altered by tuning the molar ratio of rhodium acetylacetonate and iron acetylacetonate. The particle size was tunable via control of surfactant concentration. Magnetic measurements were made for films of the particles cast onto silicon wafers. The coercivity of Fe(51)Rh(49) nanoparticles was similar to 250 Oe at room temperature after annealing at 700 degrees C for 2 h, indicating CsCl-type phase transition. The temperature dependent magnetization measurement of annealed Fe(51)Rh(49) confirmed the antiferromagnetic-ferromagnetic transition and was supported by x-ray diffraction measurements. (C) 2008 American Institute of Physics.