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通过混合物理化学气相沉积法(hybrid physical-chemical vapor deposition,HPCVD),在(000l)SiC衬底上制得一系列从10 nm到8μm的MgB2超导膜样品,并对它们的形貌、超导转变温度Tc和临界电流密度Jc与膜厚度的关系进行了研究.观察到Tc随膜厚度增加上升到最大值后,尽管膜继续增厚,但Tc值保持近乎平稳,而Jc则先随膜厚度增加上升到最高值后,继而则随膜的厚度的增加而下降.MgB2膜的Tc(0)和Tc(onset)值与膜厚的关系基本一致,Tc(0)在膜厚为230 nm处达到最大值Tc(0)=41.4 K,而Jc(5K,0T)在膜厚为100 nm时达到最大值,Jc(5 K,0 T)=2.3×108A·cm-2,这也说明了我们能用HPCVD方法制备出高质量干净MgB2超导膜.本文研究的超导膜厚度变化跨度非常大,从10 nm级的超薄膜到100 nm级的薄膜,再到几微米的厚膜,如此Tc和Jc对膜厚度变化的依赖就有了较完整、成体系的研究.并且本文的工作对MgB2超导薄膜制备的厚度选取具有实际应用意义.
A series of samples of MgB2 superconducting films from 10 nm to 8 μm were prepared on (000l) SiC substrate by hybrid physical-chemical vapor deposition (HPCVD). Their morphology, superconductivity The relationship between the transition temperature Tc and the critical current density Jc and the film thickness was studied.It was observed that the Tc value remained nearly steady despite the thickening of the film when the Tc increased with the increase of the film thickness, (0) and Tc (onset) values of MgB2 films are basically consistent with the film thickness, and Tc (0) is at a film thickness of 230 nm Reaching the maximum value of Tc (0) = 41.4 K, while Jc (5K, 0T) reached the maximum at a film thickness of 100 nm. Jc (5K, 0T) = 2.3 × 108A · cm- We can use HPCVD method to prepare high-quality clean MgB2 superconducting films.The superconducting films studied in this paper vary widely in thickness, ranging from 10 nm ultra-thin films to 100 nm thin films to a few microns thick film The dependence of Tc and Jc on the change of film thickness has a more complete and systematic study.And the work of this paper has the value of choosing the thickness of MgB2 superconducting thin films Practical application significance.