Low temperature synthesis, structural, and magnetic characterization of manganese sillenite Bi12MnO20

A low temperature (approximate to 393 K) soft chemical route under refluxing conditions has been followed to prepare polycrystalline manganese sillenites, Bi12MnO20 (BMO). X-ray diffraction and scanning electron microscopy show a cubic BMO pure phase with a=10.206 angstrom, homogeneous morphology, and nanoparticle size. A detailed study of the magnetic properties is presented. The zero-field-cooled and field-cooled magnetization curves show a typical nanoparticle behavior with blocking temperature T-B approximate to 18 K. The ac susceptibility measured at different frequencies gives an Arrhenius behavior compatible with the superparamagnetic nanoparticle relaxation processes but with an unusually small relaxation time. The relaxation time is shown to be field dependent due to strong interparticle interaction. (C) 2010 American Institute of Physics. [doi:10.1063/1.3362927]