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Electrical conductivity and dielectric behaviour of nanocrystalline La 0.6 Gd 0.1 Sr 0.3 Mn 0.75 Si 0.25 O 3

2018; Royal Society of Chemistry; Volume: 8; Issue: 17 Linguagem: Inglês

10.1039/c8ra00037a

2046-2069

Ah. Dhahri, E. Dhahri, E.K. Hlil,

Advanced Condensed Matter Physics

An La0.6Gd0.1Sr0.3Mn0.75Si0.25O3 ceramic was prepared via a solution-based chemical technique. X-ray diffraction study confirms the formation of the compound in the orthorhombic structure with the Pnma 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: σ(ω) = σdc + Aωn , where ω is the frequency of the ac field, and n is the exponent. The deduced exponent 'n' 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.