The results also showed that the formation of cobalt ferrite spinel structures is affected by synthesis methods. Both prepared techniques were effective for the production of spinel crystalline nanoparticles. Magnetic hysteresis loop data confirmed that the magnetic properties of nanoparticles depend on the structure and size of particles. | L. T. Tam, N. H. Du, L. T. H. Nhung, D. T. N. Hang, P. T. Dung, N. M. Duc, T. T. P. Thu / Characterization CHARACTERIZATION OF COBALT FERRITE CoFe2O4 NANOPARTICLES SYNTHESIZED BY CO-PRECIPITATION AND HYDROTHERMAL METHODS Le The Tam (1), Nguyen Hoa Du (1), Le Thi Hong Nhung (1) Duong Thi Ngoc Hang (1), Phan Thi Dung (2), Ngo Minh Duc (1), Tran Thi Phuong Thu (1) 1 School of Natural Sciences Education, Vinh University 2 Nghe An College of Education Received on 10/5/2017, accepted for publication on 08/7/2017 Abstract. Crystalline nanoparticles CoFe2O4 with a spinel structure were prepared by co-precipitation and hydrothermal methods. The magnetic properties of calcined cobalt ferrite formed from nano crystalline powders by these methods have been compared to each other. The dependence of the particle size and crystalline structure of obtained nanoparticles on the synthesis conditions was examined and characterized using field emission scanning electron microscope (FESEM), X-ray diffraction analysis (XRD) and energy dispersive X-ray spectroscopy (EDX). The XRD analysis revealed a high degree of crystallinity and confirmed spinel structure. The FESEM images showed the presence of spherical ferrite particles with an average diameter about 20-25 nm. The results also showed that the formation of cobalt ferrite spinel structures is affected by synthesis methods. Both prepared techniques were effective for the production of spinel crystalline nanoparticles. Magnetic hysteresis loop data confirmed that the magnetic properties of nanoparticles depend on the structure and size of particles. The materials prepared by hydrothermal route and calcination at 600ºC have had higher magnetic saturation than the non-calcined and calcined coprecipitation method samples. 1. Introduction In recent years, nanocrystalline materials are becoming a subject of intense research because of their unique properties. Magnetic nanoparticles have been of interest for their typical physical and .
