本研究藉由摻雜硫或氫氧化鋰，來改善硒化鐵的超導性質。硒化鐵存在有幾種不同的相結構，其中富鐵的相為超導相，而缺鐵的δ相為非超導的磁性相。伴隨著摻雜硫和氫氧化鋰的量增加，形成超導相所需的燒結條件和成份配比也需隨之改變，尤其鐵對其他元素的比例要有所增加。對摻雜後的樣品進行結構分析發現，隨著硫含量的增加，其結構ab平面逐漸縮小，c軸逐漸拉長，但整體體積呈縮小趨勢。對於摻雜氫氧化裡的樣品而言，隨著摻雜量的增加，不僅ab平面縮小，c軸也變短。藉由測量磁化率隨溫度的變化曲線發現，摻雜10-15%硫的樣品其超導轉換溫度(Tc)略有提高，約為9.0K左右；而摻雜20%氫氧化鋰的樣品其Tc可進一步提高至9.1K。
本研究還利用助熔劑法對摻雜的硒化鐵進行液相晶體成長。液相成長的樣品其結晶性有顯著提高，晶粒在100m數量級，而固相燒結的樣品僅有10nm左右。藉由歐傑電子能譜分析，可發現進行液相成長後的硒化鐵厚膜，其上確實有鋰的存在，顯示鋰並沒有因高溫而全部揮發不見。摻雜10-15%硫的樣品，經液相成長後Tc提升至9.3K，摻雜氫氧化鋰的樣品，Tc也略有改善。這與純硒化鐵不同，其液相成長的樣品Tc反而有所下降。

In this study, FeSex was doped with S and LiOH in order to improve the superconducting properties. There exist a few different phases for FeSex. The Fe-rich  phase is superconductive, while the Fe-deficient  phase is non-superconductive and ferrimagnetic. As the doping amount of S or LiOH increased, the composition and sintering condition for achieving the superconductive phase had to change as well. In particular, the ratio of Fe against the rest of the elements had to increase. Structural analysis on the doped samples showed that as the S content increased the a-b axes of the unit cell reduced, whereas the c axis increased. However, the overall volume of the structure was decreased gradually. For the LiOH doped samples, all the a, b and c axes were reduced. The superconducting transition temperature (Tc) was determined from the magnetic susceptibility vs. temperature measurements. The Tc of 10-15% S doped samples was increased slightly, to about 9.0 K. However, the Tc of 20% LiOH doped samples was raised further to 9.1 K.
Attempts were made to grow the thick films of the doped FeSex from high temperature solution. The samples grown from the high temperature liquid showed a much better crystallinity, with the grain size in the order of 100 m, compared to the 10 nm for the sintered powders. Auger electron spectroscopy confirmed that the thick FeSex films indeed contained Li ions, eliminating the speculation that Li might evaporate totally during the growth at high temperature. The Tc of the 10-15% S doped thick films were 9.3 K, higher than the sintered powder samples. The Tc of the LiOH doped thick films was also improved slightly. This was different from the result for the pure FeSex thick films, for which the Tc of the thick films grown from the high temperature liquid was lower than the sintered powders.

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