Effect of Fe Concentration in ZnO Powders on Ferromagnetic Resonance Spectra

Ferromagnetic resonance (FMR) investigations of nanocrystalline Zn 1− x Fe x O ( x = 0.01, 0.03 and 0.05) powders are reported. Broad FMR signals with g factor >2 representing the signature of ferromagnetism were identified. In the temperature range of 110–300 K, the magnetic field position of the resonance line shifts to lower fields and the shift increases with increasing x . The observed shift was attributed to an internal field arising from the spin sublattice within the host. The FMR line widths increase with the temperature decrease and increase with the increase in the Fe content x . This broadening is due to the presence of the non-homogeneous local magnetic fields in the investigated samples. A deviation of the experimental line shapes from the Lorentzian shape was identified in the low-temperature range.