本論文的目的是在探討第二類超導鈮薄膜線在大電流驅動後平衡的磁通
量子渦流形成結構。探討此渦流的形成和分佈不僅對闡明外加電流超越臨界電流後的崩潰機制有重要的意義，還能對實際應用面的極限能有更多理解。我們使用外部磁場、電流和溫度等變量研究鈮薄膜線中渦流之形態，並通過使用自製的掃描超導量子干涉儀顯微鏡(Scanning Superconducting Quantum Interference Device Microscope, SSQM)觀察。

本論文的內容主要包括兩部分，第一部分，我們會詳述本文使用的SSQM
系統。為了提升SSQM 之效能及簡化其製備過程，我們改進了初始系統設計。主要的改進包括集成了本實驗室先前所定制的掃描式霍爾探針顯微鏡(Scanning Hall Probe Microscope, SHPM)所使用的掃描方案、新的懸臂設計和低溫LC共振電路設計，其技術細節我們詳載於附錄中。

第二部分為主要的量測結果與討論。鈮薄膜線樣品是以直流濺鍍系統濺鍍鈮金屬，再利用圖案化技術將鈮薄膜處理成蜿蜒形式的幾何形狀而成。特別地，樣品中我們另外設計薄膜線來外加磁場以局部操縱渦流。我們採用所謂的電流加熱程序瞬時驅動超導線進入正常狀態，觀察到渦流往往形成在無序之區域，這些渦流通常是可移動的，並且可以通過使用交互磁場和發送高電流而在中心區域中減少並傾向於在圖案邊界附近積聚。我們的結果表明薄膜質量和幾何形狀對超導薄膜線的應用的重要性。

This thesis aims to investigate the configurations of equilibrium vortices formed in superconducting niobium (Nb)-thin film wire after high current drive. The formation and distribution of vortices in superconducting thin film have strong implications not only for elucidating its breakdown mechanism as the external current applied exceeds the critical current density, but also for understanding its limit in practical applications. The vortex morphology of thin-film wire is studied with the variables of external magnetic fields, currents and temperatures and is observed by using a home-made Scanning Superconducting Quantum Interference Device microscope (SSQM).

The content of this thesis is comprised by two parts. In the first part, we will describe our SSQM system. To enhance the capability of SSQM and to simplify its operation, we improve our original design. The primary improvements include the integration of the scanning scheme used in our custom-made scanning Hall Probe microscope, new cantilever design, and the low temperature tank-circuit design. We leave extensive technical details in the Appendixes.

The main results and discussions are presented in the second part. The sample made by Nb thin-film is prepared by DC sputtering and is patterned into a zigzag geometry. In particular, we employ in-suite thin-film wires to introduce magnetic field to locally manipulate the vortex. We adopt a current heating procedure to transiently drive the superconducting wire into the normal state. We observe that the vortices tend to form in the disordered regime. These vortices are in general movable, and can be depopulated in the central area and tend to accumulated near the pattern boarders, by using alternating magnetic field and sending high currents. Our results suggest the importance of thin-film quality and the geometry for the applications of superconducting thin-film wires

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