Ahmad Taufiq, Sunaryono, Edy Giri Rachman Putra, Atsushi Okazawa, Isao Watanabe, Norimichi Kojima, Suminar Pratapa, Darminto
A series of MnxFe3−xO4 (0 ≤ x ≤ 1) nanoparticles was successfully synthesized via a simple coprecipitation method. The starting material was a natural magnetite purified from local iron sand. Crystallite nanoparticles were produced by drying without using a high calcination temperature. Rietveld analysis of the X-ray diffractometry (XRD) data for all samples demonstrated that the Mn ions partially substituted the Fe ions in the spinel cubic structure of the Fe3O4 to form MnxFe3−xO4 phases. We applied two lognormal spherical and single mass fractal models to the analysis of the small-angle neutron scattering (SANS) data and revealed that the primary MnxFe3−xO4 particles ranged in size from 1.5 to 3.8 nm and formed three-dimensional clusters as secondary structures. The samples displayed superparamagnetic behavior, having the saturation magnetization which was most likely influenced by the competing contribution from Mn, the sizes of the primary particles, and their clusters. Further analysis revealed that the zero-field-cooled and field-cooled curves of the MnxFe3−xO4 nanoclusters exhibited a superparamagnetic phenomenon with the lowest magnetic blocking temperature approximately 145 K. © 2015, Springer Science+Business Media New York.
Department of Physics, Sepuluh Nopember Institute of Technology (ITS), Jalan Arif Rachman Hakim, Surabaya, 60111, Indonesia; Department of Physics, State University of Malang (UM), Jl. Semarang 5, Malang, 65145, Indonesia; Center for Science and Technology of Advanced Materials, National Nuclear Agency of Indonesia (BATAN), Kawasan Puspiptek Serpong, Tangerang, 15314, Indonesia; Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, 153-8902, Japan; Advanced Meson Science Laboratory, Nishina Center, RIKEN, 2-1, Hirosawa, Wako, Saitama, 351-0198, Japan
