Self-assembled Co₃(BO₃)₂/surfactant nanostructured multilayers

Co₃(BO₃)₂/surfactant composites have been prepared by the controlled precipitation of aqueous cobalt cations together with surfactant. The composite shows a layered structure as determined by x-ray diffraction, in which the Co₃(BO₃)₂ layers of about 6 Å in thickness are in alternation with surfactant bilayers. The temperature-dependent magnetization measured in the zero-field-cooled (ZFC) and field-cooled (FC) processes and the AC-magnetic susceptibility measured at different frequencies indicate that there is a freezing temperature at low temperature (<6 K) and the temperature is weakly frequency dependent. A clear difference between thermal remanent magnetization (TRM) and isothermal remanent magnetization (IRM) was observed at 2 K. All the experimental observations suggest that the multilayers are spinglass in nature.