Enhancement of magnetoresistance and near room-temperature temperature coefficient of resistivity in polycrystalline La0.7Ca0.24Na0.06MnO3 by silver doping

We reported the synthesis, characterization, electrical transport, and magnetic properties of polycrystalline La0.7Ca0.24Na0.06MnO3:Agy (LCNMO:Agy) with y = 0.0, 0.1, 0.2, 0.3, and 0.4. The combination of EDS and XPS proved that Ag not only entered the perovskite phase structure but there would also be a small amount of Ag enrichment at the grain boundaries. The magnetoresistance (MR) and temperature coefficient of resistivity (TCR) improved significantly with the addition of Ag as a dopant. At y = 0.2, a multi-functional perovskite material with high TCR (30.57% K−1) near room temperature and large MR (72.28%) at the low magnetic field (1 T) was obtained. This enhancement of MR and TCR near room temperature was attributed to the good connectivity between the grains and the decrease in electron scattering at the grain boundaries. Overall, these findings look promising for future applications in infrared detection bolometers.