Impedance spectroscopic characterization of gadolinium substituted cobalt ferrite ceramics

Articles you may be interested in Dielectric relaxations and alternating current conductivity in manganese substituted cobalt ferrite Impedance spectroscopy study of strontium modified lead zirconate titanate ceramics Dielectric and magnetic properties of sol-gel-derived lead iron niobate ceramics Gadolinium (Gd) substituted cobalt ferrites (CoFe 2Àx Gd x O 4 , referred to CFGO) with variable Gd content (x ¼ 0.0–0.4) have been synthesized by solid state ceramic method. The crystal structure and impedance properties of CFGO compounds have been evaluated. X-ray diffraction measurements indicate that CFGO crystallize in the inverse spinel phase. The CFGO compounds exhibit lattice expansion due to substitution of larger Gd ions into the crystal lattice. Impedance spectros-copy analysis was performed under a wide range of frequency (f ¼ 20 Hz–1 MHz) and temperature (T ¼ 303–573 K). Electrical properties of Gd incorporated Co ferrite ceramics are enhanced compared to pure CoFe 2 O 4 due to the lattice distortion. Impedance spectroscopic analysis illustrates the variation of bulk grain and grain-boundary contributions towards the electrical resistance and ca-pacitance of CFGO materials with temperature. A two-layer heterogeneous model consisting of moderately conducting grain interior (ferrite-phase) regions separated by insulating grain boundaries (resistive-phase) accurately account for the observed temperature and frequency dependent electrical characteristic of CFGO ceramics. V C 2014 AIP Publishing LLC.