Enhanced room-temperature TCR of La0.67Ca0.33-xSrxMnO3 (0.06 ≤ x ≤ 0.11) polycrystalline ceramics by Sr content adjustment. Issue 6 (15th April 2020)

• Record Type: Journal Article
• Authors: Chu, Kaili; Peng, Jubo; Li, Hongjiang; Pu, XingRui; Zhang, Shuai; Dong, Gang; Liu, Yang; Liu, Xiang
• Is Part Of: Ceramics international. Volume 46:Issue 6(2020)
• Page Start: 7568
• Page End: 7575
• Publication Date: 2020-04-15
• Subjects: La0.67Ca0.33-xSrxMnO3 (LCSMO) -- Sol-gel method -- The transition temperature of metal-insulator (TMI) -- Electrical transport properties -- Temperature coefficient of resistivity (TCR); Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2019.11.256
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Herein, the influence of Sr doping on chemical composition, microstructure, and electrical transport properties of La0.67 Ca0.33- x Sr x MnO3 (LCSMO, 0.06 ≤ x ≤ 0.11) polycrystalline ceramics is systematically investigated. The study was performed by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), elemental mapping, energy dispersive spectrometry (EDS), X-ray photoemission spectroscopy (XPS), and four-probe method ( ρ - T ). XRD results verified the synthesis of high-purity orthogonal perovskite structure with Pnma space group. EDS and XPS results confirmed presence and uniform distribution of La, Ca, Sr, Mn and O. Furthermore, ρ - T curves indicated that the resistivity decreased with increasing Sr content, whereas metal-insulator transition temperature ( T MI ) gradually increased. Moreover, cell volume ( V ) and electron bandwidth ( W ) increased with the increase in Sr content, which effectively reduced the resistivity of LCSMO ceramics. One should note that double exchange (DE) enhancement between Mn 3+ and Mn 4+ is responsible for gradually increasing T MI . Finally, maximum TCR value of 14.3% K −1 was achieved at x = 0.08, which rendered TCR peak temperature of 299.0 K. High room-temperature TCR of LCSMO ceramics is promising for next-generation infrared bolometers, operating at room-temperature.