Synthesis and magnetic properties of ZnFe1.97RE0.03O4 (RE = Eu and Nd) nanoparticles

The ZnFe1.97RE0.03O4 (RE = Eu and Nd) nanoparticles (NPs) were prepared via the sol-gel method. We investigated the effect of RE3+ doping on the spinel structure and the magnetic properties of the samples. Compared to the paramagnetism of pure ZnFe2O4, the ZnFe1.97Eu0.03O4 and ZnFe1.97Nd0.03O4 NPs exhibit weak ferromagnetic properties, since the formation of defects in ZnFe2O4 caused by RE3+ doping not only create energy levels within the band gap to hybridize with the 4f levels RE3+ and trigger the onset of magnetic order, but also work as the pinning centers to impede the rotation of the magnetization and give rise to the enhanced coercivity. Moreover, the coercivity and saturation magnetization of ZnEe(1.97)Nd(0.03)O(4) NPs are stronger than those of ZnEe(1.97)Eu(0.03)O(4) NPs due to the larger spin and orbital moments of Nd3+ ions. (C) 2014 Elsevier Ltd. All rights reserved