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

• Published in: Journal of sol-gel science and technology 2021-09, Vol.99 (3), p.627-635
• Main Authors: Yang, Yunrui, Li, Ling, Yang, Sheng’an, Ling, Fuxin, Gao, Yan, Qi, Longfei, Wu, Dingzhang, Li, Yingjuan, Zhang, Hui, Chen, Qingming
• Format: Article
• Language: English
• Subjects: Ceramics; Chemistry and Materials Science; Composites; Electrical properties; Electrical resistivity; electronic; Glass; Grain boundaries; Inorganic Chemistry; magnetic and ferroelectric applications; Magnetic properties; Magnetism; Magnetoresistance; Magnetoresistivity; Materials Science; Nanotechnology; Natural Materials; Optical and Electronic Materials; Original Paper: Sol-gel and hybrid materials for dielectric; Perovskites; Polycrystals; Room temperature; Silver; Solid phases; Temperature
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-021-05614-x

We reported the synthesis, characterization, electrical transport, and magnetic properties of polycrystalline La 0.7 Ca 0.24 Na 0.06 MnO 3 :Ag y (LCNMO:Ag y ) 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.