Electrical conductivity and dielectric behaviour of nanocrystalline LaGdSrMnSiO.

An LaGdSrMnSiO ceramic was prepared a solution-based chemical technique. X-ray diffraction study confirms the formation of the compound in the orthorhombic structure with the group space. Dielectric properties have been investigated in the temperature range of 85-290 K with the frequency range 40 Hz to 2 MHz. The conductivity spectra have been investigated by the Jonscher universal power law: ()  =     +   , where is the frequency of the ac field, and is the exponent. The deduced exponent '' values prove that a hopping model is the dominating mechanism in the material. Based on dc-electrical resistivity study, the conduction process is found to be dominated by a thermally activated small polaron hopping (SPH) mechanism. Complex impedance analysis (CIA) indicates the presence of a relaxation phenomenon and allows us to modelize the sample in terms of an electrical equivalent circuit. Moreover, the impedance study confirms the contribution of grain boundaries to the electrical properties.