成長高溫超導體釹鋇銅氧薄膜與其微波特性之研究

Abstract

本篇論文為研究釹鋇銅氧(NdBa2Cu3O7)高溫超導材料，其原因在於此材料的抗水特性極好。我們從粉末開始配製燒結，嘗試在不同通氧環境以及燒結溫度做燒結，發現在燒結的過程中氧氣必須要流通且燒結溫度為950 ˚C，塊材能得到最好的特性。此外我們用雙軸式RF磁控濺鍍的方法成長釹鋇銅氧薄膜，分別濺鍍在鋁酸鑭(LaAlO3)、鈦酸鍶(SrTiO3)以及氧化鎂(MgO)基板上。在LaAlO3基板上我們成功長出將近90 K的薄膜。 本篇論文另一個重點在於使用冷卻循環系統(Cryo-Cycle)以探針式耦合共振器的方法，量測樣品的表面電阻。我們先量測出金在77 K的表面電阻為 27.7 mΩ，接著我們量測釹鋇銅氧/氧化鎂以及釹鋇銅氧/鈦酸鍶/氧化鎂結構，以之作比較。

In this thesis, we have studied the high temperature superconductor, NdBa2Cu3O7, which has high stability against water corrosion. We mix and grind powder ,then heat in quartz tube at different temperature and different method to let gas into the tube. There are best quality of bulk in these different way is 950 ˚C under flow oxygen. We deposition the NBCO(NdBa2Cu3O7) films by dual – gun RF magnetic sputtering. We have grown the film on LaAlO3、SrTiO3 and MgO substrate and there are Tc=90 K films deposited on LaAlO3 substrate. The effect of several deposition parameters on the NBCO e.g., gas temperature, rf power were studies. The probe coupling method is the way to measure the surface resistance(Rs.).We have get the gold’s Rs , 27.7 mΩ at 77 K. Then we want to compare the Rs between NBCO/Mgo and NBCO/STO/MgO.