The Effects of Mo Partial Substitution at the Mn Site on Electroresistance Behaviour in La_0.7Ba_0.3Mn_1−xMo_xO₃ (x = 0, 0.01, 0.02, 0.03, 0.04) Manganites

In this study, the structural, electrical, and magnetic properties and electroresistance (ER) effects in La_0.7Ba_0.3Mn_1−xMo_xO₃ (x = 0–0.04) prepared using the solid-state method have been studied. All samples exhibited a metallic to insulating behaviour accompanied by ferromagnetic properties. Mo substitution increased resistivity under an applied current of 10 mA while the higher applied current of 20 mA reduced the resistivity and led to the ER effect. Mo-substituted samples exhibited almost constant and larger ER values than the x = 0 sample within a temperature range of 30–180 K, which may be due to the presence of dual double-exchange interactions of Mn²⁺-O-Mn³⁺ and Mn³⁺-O-Mn⁴⁺ along with the formation of more conductive paths in the metallic region. Meanwhile, the Mo-substituted samples exhibited a reduction in the ER effect in the insulating region which was probably due to the strong localization of charge carriers. The result was attributed to the induction of Mn²⁺ which may contribute to the lattice distortion effect and thus enhanced electron-lattice attraction in the Mo-substituted samples.