Impact of La3+doping on temperature coefficient of resistivity and peak temperature of La x Ca0.89-xSr0.11MnO3 films prepared by sol-gel spin coating method

Herein, refined LaxCa0.89-xSr0.11MnO3 (LCSMO, x = 0.65, 0.68, 0.71 and 0.74) films were prepared through the sol-gel spin-coating. The influence of La3+ content on the structural properties of LCSMO films was investigated by X-ray diffraction and Atomic force microscope, demonstrating that LCSMO films can grow well on SrTiO3 (00l) substrate. Besides, X-ray photoemission spectroscopy verified the double exchange (DE) effect was weakened with La3+ dopant. The La3+ doping and interconnected grains boundaries (GBs) led to the weakening DE effect and GBs scattering, respectively. Due to superior GBs connectivity, the resistivity of LCSMO films was less than 7.1 x 10(-4) Omega.cm at low temperature of 100 K. Importantly, it is an effective control method to keep the temperature (T-k) corresponding to temperature coefficient of resistivity (TCR) at room temperature with Sr2+ content as constant in LCSMO films. At x = 0.71, the peak TCR value was found to be 8.84%/K and corresponding T-k was 283.15 K. These results are beneficial for advanced application of uncooling infrared bolometer.

Automated summary

In this study, refined LaxCa0.89-xSr0.11MnO3 (LCSMO, x = 0.65, 0.68, 0.71 and 0.74) films were prepared using the sol-gel spin-coating method. The influence of La3+ content on the structural properties of LCSMO films was investigated, showing that LCSMO films can grow well on SrTiO3 (00l) substrate. X-ray photoemission spectroscopy confirmed the weakening of the double exchange effect due to La3+ doping. La3+ doping and interconnected grain boundaries resulted in the weakening of the double exchange effect and grain boundary scattering, respectively. The resistivity of LCSMO films was less than 7.1 x 10(-4) Ω.cm at a low temperature of 100K, attributed to the superior grain boundary connectivity. It was also found that by keeping the Sr2+ content constant, the temperature (T-k) corresponding to the temperature coefficient of resistivity (TCR) can be controlled at room temperature. At x = 0.71, the peak TCR value was found to be 8.84%/K and the corresponding T-k was 283.15K. These results are important for the advanced application of uncooling infrared bolometer.