Authors: R. Reisi Shahraki, S.A. Seyyed Ebrahimi, M. Ebrahimi
Affilation: University of Tehran, Iran, Islamic Republic of
Pages: 398 - 400
Keywords: zinc ferrite, co-precipitation, superparamagnetic, nanoparticles, magnetic properties
In this work, single phase zinc ferrite nanoparticles have been prepared by coprecipitation method at 40, 60 and 80 °C without any subsequent calcination and the effect of the reaction temperature on the composition, structural and magnetic properties of these particles have been studied. The formation of nanoparticles with different composition, microstructure, crystallite size and magnetic properties were investigated using XRD, FESEM, TEM, and VSM. The XRD patterns proved that the nanoparticles were single phase cubic spinel ZnFe2O4 with crystallite size below 10 nm (Fig. 1). It can be seen that the average crystallite size increases rapidly from 5 nm at 40 °C to 9.8 nm at 80 °C. Fig. 2 shows the FESEM images of zinc ferrite nanoparticles synthesized at various reaction temperatures. In all samples fine particles are agglomerated and form clusters. Fig. 3 shows the TEM image of ZnFe2O4 nanoparticles prepared at 60°C. Fig. 4 shows the magnetic hysteresis loops of ZnFe2O4 nanoparticles synthesize at different temperatures. As can be seen, the magnetization curves present an ‘‘S’’ shape hysteresis loop with zero coercivity showing that the as-prepared nanocrystalline zinc ferrites have superparamagnetic behaviour.