ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Characterization of NiFe₂O₄ nanoparticles synthesized by various methods

Hüseyin Kavas, Nermin Kasapoğlu, Abdülhadi Baykal, and Yüksel Köseoğlu

Department of Physics, Fatih University, B. Cekmece, 34500 Istanbul, Turkey

E-mail: hbaykal@fatih.edu.tr

Received: 4 July 2008  Revised: 28 October 2008  Accepted: 4 November 2008

Abstract: Microwave-induced combustion with glycine, CTAB-assisted hydrothermal process with NaOH and NH3, EDTA assisted-hydrothermal methods have been applied to prepare NiFe₂O₄ nanoparticles for the first time. Structural and magnetic properties of the products were investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmison electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and electron spin resonance spectrometry (EPR). TEM measurements showed that morphology of the product depends on the synthesis method employed. The average cystallite size of NiFe₂O₄ nanoparticles was in the range of 14–59 nm as measured by XRD. The uncoated sample (Method A) had an EPR linewidth of 1973 Oe, the coated samples reached lower values. The magnetic dipolar interactions existing among the Ni ferrite nanoparticles are reduced by the coatings, which could cause the decrease in the linewidth of the EPR signals. Additionally, the linewidth increases with an increase in the size and the size distribution of nanoparticles.

Keywords: magnetic materials - spinels - synthesis methods - XRD - EPR - TEM

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-009-0034-6

Chemical Papers 63 (4) 450–455 (2009)