As shown in Fig. 2.2A and B, the particles exhibit the desirable core/shell structure of carbon-coated MNPs. A typical example of the desired core/shell Fe@C particles is displayed in Fig. 2.2B which shows a spherical Fe nanoparticle of about 24 nm coated by 5 nm of carbon. The average size of the Fe particles in Fe@C amounts to 22 nm with a size distribution in the range 2–58 nm as presented in Fig. 2.2C. The phase structure measurements reveal pure Fe core with no peaks of related oxides.