Electrical conductivity in La1-xAgxMnO3 pellets between 10 and 350 K

The temperature dependence of the electrical resistivity in monovalent (Ag) substituted LaMnO3 has been investigated between 10 and 350K for both H=0 and 0.8T. The polycrystalline pellets of the composition La1-xAgxMnO3 (0 < x < 0.3) were prepared by a novel pyrophoric method. Above the metal-insulator transition temperature, the resistivity is well represented by adiabatic polaronic model, while below the peak up to about 100 K, the resistivity is governed by an equation of the type, rho = rho(0) + CTP (2 < p < 2.5). All the samples clearly reveal the existence of zero field resistivity minimum, which is influenced by applied magnetic field (H = 0. 8 T). The depth the resistivity minimum decreases considerably in presence of the applied magnetic field. Analysis of our results in terms of the model based on charge carrier tunneling between the antiferro magnetically coupled grains shows excellent agreement with the experimental data for both H = 0 and 0.8 T. (c) 2005 Elsevier B.V. All rights reserved.