Magnetic properties of manganese ferrite bixbyite

Full text: The grinding of iron and manganese oxides promoted by long periods promotes the appearance of a crystalline phase bixbyite manganese ferrite. The particles undergo mechanical stresses at their points of contact, due to compression, impact or shear average particle with other particles. And these stresses leading to deformation and elastic and inelastic if the voltage exceeds the ultimate strength of the particle, the same fracture occurs. Samples of manganese ferrite type bixbyite MnFeO₃ were obtained by mechanosynthesis in planetary mill. The samples obtained by milling and manganese III, iron II oxide were performed with times of 40, 45 and 50 hours with 250 rpm rotation rate and mass/ ball 1:10. The microstructure of bixbyite manganese ferrites are characterized by X-ray diffraction powder (XRD). The bixbyite structure is also able to accommodate ions at three distinct interstitial sites: 16c, 24d and 8b. The local environments of the interstitial sites are again different, and although all are 6-fold coordinated by oxygen ions, the 8b and 24d sites are 6-fold coordinated by cations. The magnetic properties are evaluated as a function of milling time. The saturation magnetization values which are similar when compared with samples by milling and sintered samples (~ 2.03 emu / g). The coercive magnetization decreases with milling time and differs significantly when compared to the sintered samples. (author)