Coalescence-free L1 ordering of embedded CoPt nanoparticles

Abstract

We have synthesized diluted samples of CoPt clusters and investigated by various techniques the effect of a 2 h anneal at 750 K. Transmission electron microscopy observations have put into evidence L10 chemical ordering without any detectable coalescence upon annealing. Magnetic measurements on CoPt clusters embedded in amorphous carbon have been used to provide additional and stronger evidence of the absence of coalescence. We show how the analysis of normalized ZFC curves can be used as a convenient and powerful technique to detect subtle variations in the cluster size distribution.