In this paper, Sr2Ni1−xZnxTeO6 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) double perovskite compounds were synthesised by the conventional solid-state method, and the structural, optical and dielectric properties were investigated.

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La0.7Ba0.3Mn1-xFexO3 (x = 0 and 0.02) were prepared by using solid state synthesis method to investigate the effect of Fe3+ substitution at Mn-site on electrical behaviour and structural properties. An analysis of X-ray diffraction, XRD data using refinement method shown both x = 0 and x = 0.02 samples were in single phased and crystallized in rhombohedral structural with Pnma space group. From ρ vs T curves shown resistivity decreased under increased of applied current of 10 mA to 20 mA for both samples in the temperature range of 20 K-300 K. The larger electroresistance, ER effect observed for x = 0.02 in temperature range of 20 K – 180 K compared to x = 0 sample is suggested due to the development of filamentary conduction path under increased of applied current. It is suggested that Fe substitution enhanced magnetic inhomogeneity which contribute to the growth of formation of conductive path under increased of applied current, lead to increase of ER effect. In the temperature range of 180 K – 300 K, the observed decreased in ER for Fe substituted sample (x = 0.02) is suggested due to the increased of scattering effect and reduction of available hopping site in metallic region and insulating region, respectively. Restriction in the movement of charge carrier had weakened the ER effect for Fe substituted sample. The observed ER effect indicates the compound has a potential for application such as for non-volatile memory elements.

The effects of Ga substitution at Mn site on electroresistance behaviour of La0.85Ag0.15MnO3 compound prepared by solid-state reaction method were investigated. X-ray diffraction (XRD) measurement were recorded at room temperature and refined by employing Rietveld techniques. Ferromagnetic to paramagnetic transitions behaviour have been observed from ac susceptibility results. Resistivity-temperature curve with different applied currents of 1 mA and 5 mA showed metal-insulator, MI transition temperature, TMI decreased with increased of the applied currents. The increased in applied current caused the maximum resistivity around TMI to be decreased for both samples indicated increased in charge carrier density which resulting in drop of resistivity, hence, enhanced double exchange mechanism. The electroresistance (ER) effects have been investigated. The result showed that the ER effect increases when Ga is substituted.

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