Magnetic susceptibility measurement of single iron/cobalt carbonyl microcrystal by atmospheric magnetophoresis.

In this study, the use of an innovative atmospheric magnetophoresis, which enables us to measure the mass magnetic susceptibility and mass of a microparticle simultaneously, was demonstrated. Using this technique, we determined the magnetic susceptibility of a crystalline deposit of iron/cobalt carbonyl, mainly composed of Fe(CO), which was prepared photochemically from a gaseous mixture of iron pentacarbonyl (Fe(CO)) and cobalt tricarbonyl nitrosyl (Co(CO)NO). The mass magnetic susceptibility and the characteristic relaxation time of the microcrystal were (7.0±1.9)×10 m kg and (5.6±2.2)×10 s, respectively. The observed magnetic susceptibility shows that the microparticle was paramagnetic. Assuming that the density was equal to that of Fe(CO) (2.1×10 kg m) and that the shape of the particle was spherical, a hydrodynamic radius of 4.7 μm and a mass of 0.91 ng were observed. It was suggested that Co was incorporated in Fe(CO).