Influence of surface ligands on saturation magnetization of FePt nanoparticles

The influence of organic ligands on the saturation magnetization (M(S)) of chemically disordered face-centered-cubic (fcc) FePt nanoparticles (NPs) was investigated. By increasing the basicity and/or surface coverage of ligands, the M(S) of fcc-phase FePt NPs decreases due to an increase in electron donation from the ligand to the Fe d bands. FePt NPs capped with 1-octanethiol or 1-dodecanethiol show larger M(S) than as-synthesized NPs capped with oleic acid due to a thinning of the nonmagnetic shell. (c) 2008 American Institute of Physics.