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- Title
Influence of Ag doping on room-temperature TCR of La0.67Sr0.33−xAgxMnO3 polycrystalline ceramics.
- Authors
Chu, Kaili; Li, Hongjiang; Pu, XingRui; Peng, Jubo; Liu, Yang; Dong, Gang; Zhang, Shuai; Liu, Xiang
- Abstract
La0.67Sr0.33−xAgxMnO3 (LSAMO, x = 0.00, 0.15, 0.18, 0.19, 0.20, 0.21, and 0.24) polycrystalline ceramics are prepared by the normative sol–gel method at a sintering temperature of 1450 °C for 12 h. The chemical composition, surface morphology, crystal structure, and electrical transport properties of the specimens are systematically studied by means of X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive spectrometry (EDS), X-ray photoemission spectroscopy (XPS), and four-probe method (ρ-T). XRD spectra reveal that all ceramics specimens crystallized in rhombohedron perovskite structure belonging to space group of R 3 - c . FESEM displays that the grain size first increased and then decreased with the increase of Ag doping. Large grain size could improve the electrical properties of LSAMO ceramics. The element mapping and EDS results show that specimens contain La, Sr, Ag, Mn, and O elements without any impurity. The presence of Ag element has confirmed by XPS spectra, corresponding to XRD and EDS results. By adjusting the Ag content, a wide metal–insulator transition temperature (TMI) in the range from 369.9 K (x = 0.00) to 299.5 K (x = 0.24) has achieved. At x = 0.19, the resistivity temperature coefficient (TCR) value reaches 16.19% K−1 meanwhile the peak temperature of the TCR is 297.43 K (room temperature). The results indicate that Ag doping has a significant changing on the double exchange (DE) effect and plays an important role in improving the electrical transport properties of LSAMO ceramics. Visibly, the addition of Ag as stoichiometric ratio achieves a large TCR at room temperature, which could provide favorable conditions for application in advanced uncooled infrared detectors.
- Subjects
POLYCRYSTALLINE semiconductors; X-ray powder diffraction; FIELD emission electron microscopy; PHOTOELECTRON spectroscopy; TRANSITION temperature; INFRARED detectors; CERAMICS
- Publication
Journal of Materials Science: Materials in Electronics, 2020, Vol 31, Issue 15, p12389
- ISSN
0957-4522
- Publication type
Article
- DOI
10.1007/s10854-020-03785-x