MgB_2超导薄膜正常态电阻特性研究

Study of the normal-state resistance characteristics for superconducting MgB_2 thin film

研究了MgB2超导薄膜正常态电阻的影响因素,探讨了与之相应的超导电性机制。MgB2超导薄膜样品采用两步异位退火的Mg扩散方法制备,通过电阻-温度曲线测量、扫描电子显微镜形貌观测和光学金相显微镜观察等方法研究了所制备薄膜的基本特性。实验结果表明,先驱硼薄膜的纯度严重影响着所生成的MgB2超导薄膜的转变温度,退火温度越高,影响越大;退火温度高的样品,正常态电阻大;退火时间长的样品正常态电阻大。

The influencing factor dependence of the resistance for MgB2 thin films in normal state, and the Superconducting mechanism corresponding with the normal - state resistance are entirely researched. The samples of superconducting MgB2 thin films are prepared by a two - step ex - situ magnesium - diffusion method. The main characteristics of MgB2 thin films are measured by the methods of resistance - temperature curve, scanning electron microscope and metalloscope observation. The results show that, the critical temperature of superconducting MgB2 thin films are greatly affected by the purity of pioneer boron thin films, and the higher anneal temperature is, the greater the effect is. If the anneal temperature is high and the time is long, then the normal state resistance will be large respectively.