Produção Nacional
Revisado por pares
Ac magnetic susceptibility measurements in nanoparticulate powders of iron-doped ZnO
2011; Elsevier BV; Volume: 324; Issue: 5 Linguagem: Inglês
10.1016/j.jmmm.2011.09.032
ISSN1873-4766
AutoresGustavo Franco Barbosa, F.L.A. Machado, A.R. Rodrigues, T.E.P. Alves, A. Franco,
Tópico(s)Theoretical and Computational Physics
ResumoLow 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 (1 mT) while its frequency (f) varied in the range 10–104 Hz for 5≤T≤300 K. The diluted samples presented cusps with maxima distributed around Tf=17.5±0.5 K 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=317.6 K, T0=4.65 K and τ0=10−14 s, 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 3.75–3.80 eV. The overall χac-data resembles those obtained for cluster spin-glass state.
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