Contributions of the phases in the coated samples as well as structural parameters were determined from XRD data using Rietveld refinement analysis. Magnetization of the core can be improved by adjusting the modification steps. XRD analysis result and SEM images revealed the formation of core/shell structure in the sample coated by using coprecipitation method. | VNU Journal of Science: Mathematics – Physics, Vol. 34, No. 4 (2018) 35-43 Synthesis and Characterization of NiFe2O4/ZnO core-shell Nanocomposites Dinh Khac Huy1, Nguyen Phuc Duong1,*, To Thanh Loan1, Hoang Manh Chung1, Nguyen Kim Thanh2, Vu Van Khai3 1 International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, 1 Dai Co Viet, Hanoi, Vietnam 2 Le Quy Don University of Science and Technology, Hoang Quoc Viet 236, Hanoi 100000, Vietnam 3 National University of Civil Engineering, 55 Giai Phong, Hanoi, Vietnam Received 09 November 2018 Revised 21 December 2018; Accepted 22 December 2018 Abstract: NiFe2O4/ZnO core-shell nanocomposites were prepared by two-step method. First, NiFe2O4 nanoparticles as the cores were synthesized by using hydrothermal route, and then modified by using sodium citrate. After that ZnO as the shells were coated with modified NiFe2O4 nanoparticles by two different chemical methods including hydrothermal and co-precipitation. The formation, crystal structure, morphology and magnetic properties of the uncoated and coated samples were investigated by using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and vibrating sample magnetometer. It was shown that the core nanoparticles are single NiFe2O4 phase with cubic spinel structure. Sodium citrate was well bonded to the surface of the modified nanoparticles. Contributions of the phases in the coated samples as well as structural parameters were determined from XRD data using Rietveld refinement analysis. Magnetization of the core can be improved by adjusting the modification steps. XRD analysis result and SEM images revealed the formation of core/shell structure in the sample coated by using coprecipitation method. Keywords: NiFe2O4/ZnO, core-shell, morphology, crystal structure, magnetization. 1. Introduction Nano-ferrites with many special properties compared to bulk materials such as high thermal .
