Study on electrical transport and relaxation process of ceramic-based nanocomposites of (1− x ) BiFeO 3 - x CoFe 2 O 4 ( x = 0.0, 0.2, 0.5, 0.8, 1.0)

The multiferroic nanocomposite samples [(1− x ) BiFeO 3 - x CoFe 2 O 4 with x = 0.0, 0.2, 0.5, 0.8, and 1.0] were synthesized by the hybrid processing method. The presence of both ferroelectric and ferromagnetic phases in the samples was confirmed by the X-ray diffraction. The lattice distortion of bismuth ferrite (BFO) occurs with the incorporation of cobalt ferrite (CFO) in the samples. From studies of the complex modulus and impedance spectroscopy, both grains and grain boundaries have a significant contribution to the electrical response of the nanocomposite samples. All samples show depressed semi-circular arcs and non-Debye type relaxation behavior. The AC conductivity was analyzed by using Jonscher’s Universal power law, σ ac = σ dc + Aω s . The correlated barrier hopping (CBH) model is the most suitable conduction mechanism to explain the transport properties of the samples. The increase in AC conductivity from 1.208 × 10 −4 S m −1 to 1.370 × 10 −3 S m −1 with increasing ferromagnetic phase was explained by effective potential barrier height ( W M ), characteristic relaxation time ( τ 0 ) and hopping distance ( R w ). The presence of the different slopes in the Arrhenius plots suggests the presence of different conduction processes in the nanocomposites. The results are analyzed in light of the literature. Graphical abstract