Preparing NiFe2O4 magnetic nanoparticles and their properties

Over the past several years, the preparation and characterization of nanoscale magnetic materials have attracted much attention as the materials in this size range would allow investigating the fundamental aspects of magnetic-ordering phenomena in magnetic materials with reduced dimensions and could also lead to new potential applications. Nanocrystalline spinel ferrites with the general formula MFe2O4 (M=Divalent metal ion) are very important magnetic materials because of their interesting magnetic and electrical properties. Various preparing methods are developed for this kind of materials named ferrite. Hydrothermal method is one of the most successful one for preparing of various materials and especially in preparing of magnetic nanocrystalline and developing their properties. Therefore in this study hydrothermal method was used to produce nanoparticles. In this study, the produced NiFe2O4 nanoparticles were annealed at 1073K, 1173K, 1273K, 1373K and 1473K for 3 hours. For structural properties IR, XRD, FESEM, EDX, DTA, TGA and DSC analysis were performed and for the magnetic properties VSM(Vibrating Sample Magnetometer) system was used. The NiFe2O4 nanoparticles was synthesized homogeneously and it was found that the size of particles is about 10-11 nm. The structural investigations clearly indicated that produces nanoparticles has no impurities. After annealing, the size of nanoparticles was increased up to about 85 nm. It was observed that the saturation magnetization and grain size increase with increasing annealing temperature. On the other hand the coercivity values decreases with increasing annealing temperature. The effects of annealing temperature on the magnetic properties were discussed on the basis of the cation distribution variation and lattice parameters. ANAHTAR KELMELER: Ferrites, Ferrimagnetism, Hydrothermal Process, Nanoparticles, Soft Magnetic Materials