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

Abstract The ZnFe 1.97 RE 0.03 O 4 (RE=Eu and Nd) nanoparticles (NPs) were prepared via the sol–gel method. We investigated the effect of RE 3+ doping on the spinel structure and the magnetic properties of the samples. Compared to the paramagnetism of pure ZnFe 2 O 4 , the ZnFe 1.97 Eu 0.03 O 4 and ZnFe 1.97 Nd 0.03 O 4 NPs exhibit weak ferromagnetic properties, since the formation of defects in ZnFe 2 O 4 caused by RE 3+ doping not only create energy levels within the band gap to hybridize with the 4f levels RE 3+ 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 ZnFe 1.97 Nd 0.03 O 4 NPs are stronger than those of ZnFe 1.97 Eu 0.03 O 4 NPs due to the larger spin and orbital moments of Nd 3+ ions.