Effects of rare-earth doping on transport properties in isoelectronic perovskite manganites

In this work, we explore the temperature dependence transport properties of isoelectronic manganites Ca0.85Re0.15MnO3 (Re = La, Pr, Nd, Gd). Substitution of Re3+ for Ca2+ will bring Mn3+ ions and hopping between Mn3+ and Mn4+ facilitated by double exchange (DE) interactions is responsible for augmentation the electrical conductivity. Resistivity shows insulating behavior with an inflection near charge ordering temperature (TCO). ρ (T) follows Mott-type variable range hopping (VRH) for all the samples in the low-T region.