Size-Dependent Magnetic Properties of Colloidal Mn3O4 and MnO Nanoparticles

Highly crystalline and monodisperse MnO and Mn3O4 nanoparticles are prepared by thermal decomposition of [Mn(acac)2] in oleylamine under an inert atmosphere in the presence and absence of a small amount of water, respectively (see picture). The particle size of both manganese oxide systems can be easily manipulated by changing the employed reaction temperature, and it has been demonstrated that the magnetic behavior depends on the size of the particles.