Magnetic properties of Zn1−xMnxFe2O4 nanoparticles prepared by hydrothermal method

Abstract

Zn1−xMnxFe2O4 nanoparticles (x=0, 0.2, 0.4, 0.6, 0.8, and 1) were prepared by a novel hydrothermal method. The obtained samples were characterized by XRD, SEM, TEM, FT-IR, VSM, and XANES. The results of XRD, SEM and TEM showed that all samples were cubic spinel structure with the crystallite size in the range of 12–18nm. Lattice parameters were found to be increased with increasing Mn content. The IR spectra of Zn1−xMnxFe2O4 nanoparticles revealed the intrinsic stretching vibrational modes of the metals at the tetrahedral and octahedral sites. The measurements of magnetic properties at room temperature by VSM show that all samples behaved ferromagnetic with magnetization (M) and coercivity in the range of 16–43emu/g and 32–72 Oe, respectively. These results indicate that some Mn2+ ions can substitute Fe2+ ions at the B site and some Mn3+ ions can substitute Fe3+ ion at both A and B sites. XANES results obtained at the Zn, Mn and Fe K-edge confirm that the oxidation state of Zn is +2 and those of both Mn and Fe are the same with the value of +2 and +3. In addition, the simulation XANES spectra confirm the existence of ZnFe2O4, (Zn,Mn,Fe)3O4 and (Mn,Fe)2O4 phases in samples which cause the decrease of the magnetization.