Magnetic study on Co3O4 nanoparticles

Magnetization measurements for the Co3O4 nanoparticles were performed. From the X-ray diffraction patterns Co3O4 nanoparticles surrounded by amorphous SiO2 were expected for the samples annealed between 623 and 873 K. Their diameters were estimated to be 2 or 3 nm. DC magnetization curves of zero-field cooled and field-cooled bifurcated around T-t = 10 K, while the bulk Co3O4 crystal exhibits antiferromagnetic transition temperature at T-N = 33 K. Characteristic properties of extremely small Co3O4 nanoparticles were confirmed. (C) 2003 Elsevier B.V. All rights reserved.