An investigation on the conductivity, electric modulus and scaling behavior of electric modulus of barium titanate-lithium ferrite composite doped with Nb, Gd and Sm

The (90)BaTi(1-2x) RxNbxO3+(10)Li0.5Fe2.5O4 (R = Gd, Sm and x = 0, 0.05, 0.1) composites are prepared using solid state method. The structural properties like X-ray diffraction (XRD), FESEM electrical properties like electric modulus (M′), complex electric modulus (M″) and conductivity properties of doped and undoped composites have been discussed. The XRD studies confirm the incorporation of Gd and Sm in the composite. FESEM reveals an increase in the average grain size of composite upon doping with Gd/Nb and Sm/Nb. The conductivity and the real electric modulus (M′) of composites are increases steeply with increase in frequency at all temperatures. The real electric modulus (M′) of composites confirms the occurrence of dispersion in all composites at all temperatures. The imaginary electric modulus (M″) increases with frequency and exhibits a peak at a certain frequency. The peaks of complex electric modulus (M″) of composites have shifted towards higher frequency with temperature. The shift of the relaxation peak towards higher frequencies upon heating suggests the decrease in the relaxation rate of the process. •The XRD pattern of Gd/Nb and Sm/Nb doped 90BT+10LF composites confirm the tetragonal perovskite structure with incorporation of minor ferrite phase.•All the micrographs exhibit dense microstructure and the grain boundaries are very clearly seen.•The conductivity of BSN-0.05 is more than 90BT+10LF, BGN-0.05, BGN-0.1 and BSN-0.1. The increase in the conductivity of composites with the temperature represents the semiconducting behavior of material.•The electric modulus (M′) of 90BT+10LF shows dispersion with increase in the temperature at higher frequencies.•The shift of the relaxation peak towards higher frequencies upon heating suggests that the relaxation rate of the process decreases with an increase in the temperature.•The changes in barrier heights represent the dielectric relaxation correlation with electrical conductivity through relaxation type at high temperature region.•The presence of Debye relaxation in all the composites can be confirmed from the semicircle of all composites.•In all composites, the dynamic process arising at different frequencies indicates that the activation energy is not same.