Ac magnetic susceptibility measurements in nanoparticulate powders of iron-doped ZnO

• Published in: Journal of magnetism and magnetic materials Vol. 324; no. 5; pp. 660 - 664
• Main Authors: Barbosa, G.F., Machado, F.L.A., Rodrigues, A.R., Alves, T.E.P., Franco, A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2012; Elsevier
• Subjects: Combustion; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cusps; Exact sciences and technology; Magnetic fields; Magnetic permeability; Magnetic properties and materials; Magnetic properties of nanostructures; Magnetic property; Magnetic semiconductors; Magnetic susceptibility; Magnetometer; Maxima; Nanomaterials; Nanostructure; Physics; Semiconductor; Studies of specific magnetic materials; Magnetic property; Magnetometer; Semiconductor; Combustion synthesis; Spin glasses; Impurity density; Critical points; Doping; Magnetic field effects; Semimagnetic semiconductors; Cluster glass; Magnetic susceptibility; Nanoparticles; Energy gap; Zinc oxide; Iron additions; Nanopowder; Activation energy
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2011.09.032

Low temperature (T) ac magnetic susceptibility (χac) measurements were performed in powder samples of the Zn1−xFexO (x=0–0.078) prepared by a combustion reaction method. The amplitude of the ac magnetic field was kept constant (1mT) while its frequency (f) varied in the range 10–104Hz for 5≤T≤300K. The diluted samples presented cusps with maxima distributed around Tf=17.5±0.5K while no such feature was observed for the pure sample (x=0). The cusp was found to become more pronounced with the increasing Fe content. Also it decreased and shifted to higher values of T by increasing f. The shift in Tf was found to follow a Vogel–Fulcher law with Ea/kB=317.6K, T0=4.65K and τ0=10−14s, for the activation energy, critical temperature and characteristic time-constant, respectively. The energy gap of the sample was measured and they were found to vary in the range 3.75–3.80eV. The overall χac-data resembles those obtained for cluster spin-glass state. ▸ Low temperature (T) ac magnetic susceptibility (χac) measurements. ▸ Zn1−xFexO prepared by a combustion reaction method. ▸ Spin-glass phase. ▸ High energy gap semiconductors.