Current induced effect on the resistivity in La0.8−xDyxNa0.2MnO3 monovalent doped manganites

Abstract

The observation of electroresistance, ER effect in several substituted doped manganites which characterized the sensitivity of sample’s resistivity to the change of applied current was suggested can be enhanced by the presence of magnegtic inhomogenity. However, such effect is not well understood but the magnetic inhomogenity may influence the strength of ER related mechanism, hence current induced effect on the resistivity in monovalent doped La0.8−xDyxNa0.2MnO3 (x = 0.00–0.20) manganites prepared using solid state reaction method have been investigated to elucidate the matter. The ρ vs T curves shown that all samples exhibit smaller resistivity under higher applied current of 10 mA as compared to 5 mA of applied current in the wide temperature range of 30 K–300 K which led to ER effect. Measurement of ac susceptibility show that x = 0 sample exhibit ferromagnetic behaviour while both Dy substituted samples exhibit ferromagnetic to paramagnetic transition behavior with reduction in Tc values. Large ER effect with value of 130% at 300 K observed in ER vs. T curve for x = 0.1 sample, while for x = 0 the ER value is 9% indicates improved sensitivity of the Dy substituted sample towards electric field. While x = 0.20 sample exhibit double ER peaks which may related to presence of impurity phases. It is suggested Dy substitution induces magnetic inhomogeneities which favors formation of more filamentary conductive paths under the presence of high applied current thus enhanced the conduction process of charge carriers. The finding on the enhancement of ER effect indicates that the Dy substituted sample as potential candidates for spintronic-based devices.