Enhanced Electrical Properties of La_{0.7}(Ca_{0.2}Sr_{0.1}) MnO_{3} Polycrystalline Composites with Ag Addition

La\(_{0.7}\)(Ca\(_{0.2}\)Sr\(_{0.1}\))MnO\(_{3}\):Ag\(_{x }\)(LCSMO:Ag\(_{x}\), x = 0, 0.1, 0.2 and 0.3, mol%) polycrystalline composites were prepared by a solid-state reaction method. With the increasing of Ag addition, the temperature coefficient of resistance (TCR) and the metal-to-insulator transition temperature (\(T_\mathrm{p}\)) reach the maximum values of 9.1 % K\(^{-1}\) and 258 K for LCSMO:Ag\(_{x}\) (x = 0.3) sample, which can be used as a candidate of bolometer or infrared detectors. The improvement of Mn\(^{4+}\) concentration and grain connectivity by Ag addition is responsible for the enhancement of \(T_\mathrm{p}\) and TCR values. The fitting curves of electrical resistivity show that the low temperature region (\(T T_\mathrm{p}\)) is fitted with adiabatic small-polaron hopping mechanism.