EuS nanoparticles were synthesized by solution-phase thermolysis of the diethylammonium salt of the anionic europium dithiocarbamate complex, [Eu(S 2 CNEt 2 ) 4 ] -. Oleylamine and triphenylphosphine were used as surfactants to prevent nanoparticle agglomeration and stabilize particle growth. By varying the synthetic parameters such as reaction temperature, heating time, and the [surfactant]:[precursor] ratio, nanoparticles of different sizes were obtained. The size-dependent magnetic properties of these nanoparticles were studied, and it was observed that a decrease in the ferromagnetic ordering temperature occurs with decreasing particle size.

We have prepared gadolinium doped europium sulfides, Eu(1-x)Gd(x)S for a doping range of 0 ≤ x ≤ 0.1 by thermal decomposition of the precursors Eu(S(2)CNEt(2))(3)Phen/Gd(S(2)CNEt(2))(3)Phen with respective ratios. Electron doping provides indirect evidence for the magnetic coupling through carrier electrons in magnetic semiconductors. Based on the magnetic properties, we determined that the paramagnetic Curie temperature, Θp, varies with doping level, in a similar way to Eu(1-x)Gd(x)O exhibiting a significant increase at low doping levels. All materials have been characterized by X-ray powder diffraction, magnetic measurements, ICP-MS, and TEM.

Surface attachment of the manganese-oxo cluster known as Mn-12 provided aqueous solution stabilization that allowed investigation of the use of the cluster as an MRI contrast agent.