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采用了化学气相沉积法(CVD),在低真空环境下制备出Mg B_2超导薄膜,并探索了退火温度、退火时间、降温速率对Mg B_2薄膜性能的影响。采用X射线衍射仪、扫描电镜和低温电导率测试系统对样品的晶体结构、表面形貌和超导电性进行了系统分析。研究表明:退火温度在780℃,退火时间为120min,退火后的降温速率控制在16℃/min左右,制备出的Mg B_2薄膜超导转变温度T_(c(onset))为39.5K,超导转变宽度ΔT_c为2K,表现出最优的超导性能,同时薄膜的成品率显著提高。证明了通过优化后,退火工艺可以显著提高Mg B_2的超导性能。
Mg B 2 thin films were prepared by chemical vapor deposition (CVD) in low vacuum environment. The effects of annealing temperature, annealing time and cooling rate on the properties of Mg B 2 thin films were also investigated. The crystal structure, surface morphology and superconductivity of the samples were systematically analyzed by X-ray diffraction, scanning electron microscopy and low temperature conductivity test system. The results show that the annealing temperature is 780 ℃, the annealing time is 120min, and the cooling rate after annealing is controlled at about 16 ℃ / min. The superconducting transition temperature T c (onset) of prepared Mg B_2 thin film is 39.5K, The transition width ΔT_c is 2K, showing the best superconducting properties with significantly improved film yield. It is proved that the annealing process can significantly improve the superconducting properties of Mg B_2 after optimization.