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本文报道了利用混合物理化学气相沉积方法(HPCVD)在SiC衬底上制备出约150 nm厚,结构均匀的MgB2薄膜.由R~T曲线知道样品TC(0)高达40.1K.由M~T曲线知道其TC=40.4K,且曲线转变十分陡峭.X射线衍射分析表明薄膜具有较好的C轴取向,没有氧污染,却存在Mg的杂峰.由M~H曲线,利用毕恩模型计算得到了5 K零场条件下JC(0T,5K)=2.7×106A/cm2,Hc2=19.5 T.这些结果表明过量的Mg对MgB2薄膜的转变温度以及有些性质有较大的影响.
This paper reports the preparation of a MgB2 thin film about 150 nm thick and uniform in structure by hybrid physical and chemical vapor deposition (HPCVD) method. The RTC curve shows that TC (0) is as high as 40.1 K and the M ~ T curve Knowing that its TC = 40.4K, and the curve transition is very steep.X-ray diffraction analysis showed that the film has a good C-axis orientation, there is no oxygen pollution, but there is a miscellaneous peak of Mg.M ~ H curve, calculated using the Bien model JC (0T, 5K) = 2.7 × 106A / cm2 and Hc2 = 19.5T under zero field conditions at 5 K. These results show that excessive Mg has a great influence on the transition temperature and some properties of MgB2 thin films.