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

作者：Barbosa G F; Machado F L A; Rodrigues A R; Alves T E P; Franco A Jr^*

来源：Journal of Magnetism and Magnetic Materials, 2012, 324(5): 660-664.

DOI：10.1016/j.jmmm.2011.09.032

• Semiconductor
• Magnetometer
• Magnetic property

Low temperature (T) ac magnetic susceptibility (chi(ac)) 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 10-10(4) Hz for 5 %26lt;= T %26lt;= 300 K. The diluted samples presented cusps with maxima distributed around T-f= 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 T-f was found to follow a Vogel-Fulcher law with E-a/k(B)=317.6 K, T-0=4.65 K and tau(0)=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 chi(ac)-data resembles those obtained for cluster spin-glass state.

• 出版日期2012-3