Structural and transport properties of La1−xAgxMnO3 (x=0.075, 0.1, 0.125 and 0.15) manganites

The structural, transport and magneto-transport properties of polycrystalline La1−xAgxMnO3 (x=0.075, 0.1, 0.125 and 0.15) are investigated. Structural symmetry with rhombohedral R  3¯C phase is revealed for all synthesized samples. Using four-probe method in the range 5–300 K, the temperature dependence of electrical resistivity shows that all samples undergo an insulator–metal (I–M) transition having a peak at transition temperature TP. The electrical resistivity data for TTP, adiabatic small polaron conduction is appropriate. The existence of a resistivity minimum (Tmin≈30 K) is influenced by an applied magnetic field (H=4 and 8 T) and is based on Coulomb interaction between carriers strongly enhanced by disorder and Kondo-like spin dependent scattering. The application of magnetic field results in the disappearance of the Kondo term.