退火工艺对制备二硼化镁超导薄膜的影响

Effect of annealing process on superconducting magnesium diboride films prepared by chemical vapor deposition

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。

MgB2 superconducting thin films were prepared in low vacuum environment using chemical vapor deposition meth- od. We studied the influence of annealing temperature, annealing time and cooling rate on the performance of MgB2 films. The crystal structure, surface morphology and superconductivity of MgB2 thin films were characterized by X - ray diffraction, scanning electron microscopy and four- point probe measurement, respectively. When the annealing temperature was held at 780℃, the an- nealing time set to 120 min and the cooling rate at 16℃/min,the sample showed the best superconducting performance. We a- chieved the highest transition temperature Tc（onset） at 39.5K with the superconducting transition width △Tc 2K. Our results demonstrate that the superconducting performance of MgB2 thin films can be significantly improved by optimized annealing process, which has a potential benefit to future industrial mass production.