Study of Some Electric, Magnetic and Dielectric Properties of Ni-Zn Spinels Ferrite

Abstract

In the present work FT- IR spectra, magnetic properties, dc conductivity, the dielectric constant and the dielectric loss tangent are investigated at room temperature and elevated temperatures. Experimentally the mixed ferrite Ni1-xZnxFe2O4 (where x=0.0, 0.2, 0.4, 0.6, 0.8 and 1) were prepared from high purity oxides using standard ceramic technique. The FT- IR spectra in the range from 350 to 1000 cm-1 were reported. Mainly ,two bands were observed. The first band at around 400 cm-1 nO and the second band at around (600-550cm-1) vT were assigned to the octahedral and tetrahedral complexes, respectively. Furthermore, the magnetization M was measured at room temperature in the range of magnetizing field H from 0 up to 3500Am-1. The results indicated that the increasing of the magnetization as Zn2+ ions increased for samples of x≤ 0.6 while the magnetization of the samples of x ≥ 0.8 decresed when Zn2+ ionincreased. The conductivity was measured as a function of temperature and the relation between lnσ (Ω.cm)-1 with temperature indicate that the conductivity is increased with temperature which revel that the samples under investigation has a semiconductor behavior. Also from the relation between ln(σT) and temperature showed that there are two different slops , this change of slope is attributed to the change of samples from ferrimagnetic to paramagnetic "curie point" .And its found that the curie point decrease as Zn2+ increased. To determine the Curie point, the inductance was measured as a function of temperature for the above investigated ferrite. The inductance seems to be constant till curie point temperature Tc, at this temperature T(K) the inductance decreases sharply. Tc was also found to decrease with increasing the Zn2+ ions. Dielectric properties such as dielectric constant ε, and the dielectric loss tangent tan (δ) has been investigated in the range of frequency at room temperature. It was found that the value of ε and tan (δ) decrease continuously with increasing frequency , this is attributed to the mechanism of polarization process in the ferrite which is similar to that of the conduction process.