La_(0.6)Sr_(0.4)CoO_3薄膜的制备及NTC特性研究

为研制具有较低室温电阻值的NTC薄膜热敏电阻,以La0.6Sr0.4CoO3陶瓷为靶材,采用RF磁控溅射法,在Al2O3基片上沉积了La0.6Sr0.4CoO3(LSCO)薄膜。研究了溅射过程中氩氧体积流量比对LSCO薄膜结晶性能和方阻的影响以及LSCO薄膜的阻温特性。结果表明:随着氩氧体积流量比的增加,LSCO薄膜的主晶相衍射峰强度及方阻均先增大后减小。LSCO薄膜具有显著的NTC特性,室温时的电阻温度系数α25为2.24×10–5;其lnR-T–1曲线具备良好的线形度,线性偏差仅为2.09%;另外,其室温时的电阻R25仅为18.75k?。

Preparation and NTC behavior of La0.6sr0.4CoO3 thin films

In order to develop a kind of NTC thin film thermistor with low room temperature resistance R25, La0.6Sr0.4CoO3 (LSCO) thin films were deposited on the Al2O3 substrate by the RF magnetron sputtering method with LSCO ceramic as the target material. The effects of volume flux ratio of argon to oxygen during the sputtering process on the crystallization behavior and square resistance of the LSCO thin films were studied. The resistance-temperature behaviors of the LSCO thin films were also investigated. The results show that both the diffraction peak intensity of main crystal phase and the square resistance of the LSCO thin films increase first and then decrease with increasing volume flux ratio of argon to oxygen. The LSCO thin films show a significant NTC behavior with a room temperature -resistance coefficient α25 of 2.24×10–5, and their lnR-T–1 curve slightly deviates from the line LnR = 3.72+1.99×103/T (SD=2.09%). Moreover, the R25 of the obtained LSCO thin films is only 18.75 kΩ.