Synthesis and characterization of amorphous Fe80−xCrxB20 nanoparticles

We report the preparation of amorphous Fe80−xCrxB20 nanoparticles by chemical reduction, their morphological and structural characterization and the study of their magnetic properties by means of Mössbauer and magnetization measurements. The results show that the mean particle size is composition dependent, decreasing with increasing x. The magnetic properties, determined by the chemical composition and by the particle size distribution, change with increasing x from a ferromagnetic character to a state characterized by the coexistence of Fe-Cr-B ferromagnetic particles with a growing fraction of antiferromagnetic (partially oxidized) and paramagnetic (oxidized) particles.