Abstract:
Nano crystalline ferrites, especially spinel ferrites, evoked greater attention in this decade
because of their technological applications. Properties of nano ferrites could be easily
tailored by the incorporation of suitable divalent, trivalent or tetravalent impurities into
the spinel structure. In this work, CuFe2O4 and Cu0.85Cd0.1Zn0.05Fe2O4 nanocrystals were
synthesized using sol-gel route. The effect of Cd2+
and Zn2+
ions doping on thermal,
structural, electrical and dielectric properties of CuFe2O4 were investigated using
powdered X-ray diffraction (XRD), thermogravimetric and differential thermal analysis
(TGA-DTA), ultraviolet visible spectroscopy (UV-vis) and complex impedance
spectroscopy (CIS).
Adding of Cd2+
and Zn2+
ions into the Cu-ferrite samples made a change in structural,
optical, electrical as well as dielectric properties. The average crystallite size was found to
increase from 26.54nm to 26.66nm after doping Cd and Zn ions due to the larger value of
dopants ionic radii. The estimated band gap energy was found to decrease from 3.3 eV to
3.1 eV due to the substitution of Cd and Zn. Impedance spectra showed a single semi-
circle for both samples which revealed that a predominant conduction takes place through
grain volume only and the contribution of grain boundary did not appeared in the
measured frequency range. The variation of dielectric constant and ac conductivity for
both samples were studied as a function of frequency in the range 20Hz to 1MHz at room
temperature and the dielectric constant was found to decrease with increase in frequency
and the ac conductivity showed an increasing trend with increase in frequency.
