Finite size effects on the structural and magnetic properties of sol-gel synthesized NiFe2O4 powders

• Published in: Journal of magnetism and magnetic materials Vol. 302; no. 1; pp. 190 - 195
• Main Authors: GEORGE, Mathew, JOHN, Asha Mary, NAIR, Swapna S, JOY, P. A, ANANTHARAMAN, M. R
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Science 01.07.2006
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic properties and materials; Physics; Grain size; Nickel oxides; Finite size effect; Powders; Magnetization; XRD; Nickel ferrite; Strain; Ferrites; Nanoparticles; Spinels; Size effect; Coercive force; Iron oxides; Sol-gel process; Magnetic properties
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2005.08.029

Nanoparticles of nickel ferrite have been synthesized by the sol-gel method and the effect of grain size on its structural and magnetic properties have been studied in detail. X-ray diffraction (XRD) studies revealed that all the samples are single phasic possessing the inverse spinel structure. Grain size of the sol-gel synthesized powders has been determined from the XRD data and the strain graph. A grain size of 9nm was observed for the as prepared powders of NiFe2O4 obtained through the sol-gel method. It was also observed that strain was induced during the firing process. Magnetization measurements have been carried out on all the samples prepared in the present series. It was found that the specific magnetization of the nanosized NiFe2O4 powders was lower than that of the corresponding coarse-grained counterparts and decreased with a decrease in grain size. The coercivity of the sol-gel synthesized NiFe2O4 nanoparticles attained a maximum value when the grain size was 15nm and then decreased as the grain size was increased further.