Propriedades estruturais e magnéticas de nanopartículas de ferritas de manganês (MnFe2O4) sintetizadas via método sol-gel usando água de coco in natura como agente quelante

Abstract

In this work, manganese ferrite nanoparticles were synthesized by the sol-gel method using coconut water as a natural chelating agent. The influence of pH on the structural and magnetic properties was investigated. For the synthesis of nanoparticles, two different solutions were prepared by dissolving about 5,2 grams of nonahydrate iron nitrate and 0,95 grams of manganese acetate in 25 ml of mature coconut (green). Solutions were mixed, and then this procedure was repeated until achieving 5 solutions. Subsequently, the pH was adjusted using a NaOH 1M solution. The results of X-ray diffraction showed that the samples exhibit single phase MnFe2O4 with cubic structure belonging to the Fd-3m space group. The size of crystallites calculated by the Scherer method ranged 10,10 and 16,76 nm. The analysis by Williamson and Hall method indicated that samples have a homogeneous size distribution subjected to a stretching of the network system. Transmission electron microscopy revealed that the particles have irregular shapes and are bonded. Samples have ferromagnetic character and its magnetic properties showed an increase in their actions because increase in pH with saturation magnetization between 50,62 and 63,85 emu / g, remnant magnetization from 1,69 and 6,37 emu / g, coercivity in the range of 14,49 and 87,10 Oersted and magnetic anisotropy in the range 1620 and 1810 erg / cm3. Therefore, this work presents a new synthesis route for manganese ferrite nanoparticles, contributing to further research in nanoscience and nanotechnology, areas as explored lately and that has aroused the interest of many researchers due to wide applicability technology and, especially, because of the fascinating properties that nanomaterials present.