Structural and temperature dependent dielectric properties of doped Mn ferrite system

Abstract

In this work, we have synthesized the Mn1-xAxFe2O4 (A = Zn, Cr; x = 0.5) ferrites. The synthesis of nanoparticles is done with the help of a low temperature gel autocombustion method. Structural confirmation of the nanoparticles is performed by the X-ray diffraction method. A synchrotron X-ray source is also used for structural analysis. Both methods approve the construction of a single phase of Cr doped ferrite, while a small amount of impurity phase of α-Fe2O3 is observed in Zn doped Mn ferrite. With the doping of Cr ions, particle size is enhanced. Dielectric spectroscopy is used to observe the effect of larger Cr ions on the ferrite system. Also, a dielectric study has been performed at high temperatures to see the impact on tangent loss, conductivity, and dielectric behavior. The result shows that the dielectric constant for both samples increases with the rise in temperature. The same behavior is observed in both samples when they are studied with respect to changes in frequency. Zn and Cr doped Mn ferrite samples sintered at 800 °C showed higher ac conductivity with 1.39 × 10−2 S m−1 and 1.0 × 10−2 S m−1 at 300 K and increased to 1.08 × 10−1 S m−1 and 0.1 × 10−1 S m−1 at 573 K when the applied frequency was 10 MHz. The activation energy for the Cr doped sample is marginally higher than the Zn doped sample observed at 1 MHz. This makes the Cr doped Mn ferrite sample a potential candidate for storage device applications as compared to Zn doped Mn ferrites.