Electrical Properties of Ag–La0.67Sr0.33MnO3
A series of La0.67Sr0.33MnO3/Ag composites were synthesized using a sol-gel method followed by a conventional solid-state reaction route. The temperature dependence of the magnetic properties and electrical resistivity has been investigated between 80 and 450 K. Except for the sample with x = 0.01, Ag addition has increased the conductivity of this system dramatically. Curie temperature (TC) is almost independent of Ag content and is 352 K for Ag-dopant samples, while the metal–insulator transition temperature TP increases with Ag addition, which is mainly due to the improvement of grain boundaries and opening a new metal conductivity channel caused by the segregation of Ag on the grain surfaces. At low temperature, the ρ - T curves are fitted well by the expression of ρ= ρ0 + ρ2T2 + ρ4.5T4.5 while all data for the above TC can be fitted by using the adiabatic small-polaron-hopping model ρ = ρ0T exp(E/kBT ).
Yi Tan and Dongying Ju
B. X. Huang "Electrical Properties of Ag–La0.67Sr0.33MnO3", Materials Science Forum, Vols. 675-677, pp. 1101-1104, 2011