在雙晶基板上之釔鋇銅氧超導薄膜的晶界傳輸特性研究

Abstract

我們用脈衝雷射蒸鍍法在失配角為 36.8 度的鈦酸鍶雙晶基板上，蒸鍍釔 鋇銅氧超導薄膜，以獲得一確知位置的晶界，並對其研究傳輸特性。在經 過晶界的電阻與溫度關係曲線裡，我們發現了符合熱活化相滑移 (Thermally Activated Phase Slipage，TAPS)效應。而其電流與電壓的 特性曲線，則發現符合電阻分路介面(Resistivity Shunted Junction， RSJ)模型，證實了我們的晶界是一 Josephson 弱連接。同時我們利用 TAPS 效應及臨界電流與溫度的關係，找出我們的晶界性質是介於 SIS和 SNS 之間。另外，我們也在量測中，加入 12.4 GHz 的微波照射，在電磁 與電壓的特性曲線中，看到了微波感應台階；而在電阻與溫度的關係曲線 □，則發現了低於臨界溫度的電阻跳動現象。 The transport properties of the bicrystalline YBCO supercounducting thin film grain boundary deposited on SrTiO3 bicrystal substrate with misorientation angle 36.8 by laser ablation have been investigated systematically. We have manifested that these samples behave as a near-ideal resistivity-shunted junction (RSJ) with the aid of analysis of our experimental observation. For example, the temperature dependence of resistivity can be interpreted in terms of the model of thermal activated phase slipage (TAPS) effect. The current-voltage characteristic for these samples with or without microwave irradiation can also be verified as well. Note that the exponent, n, of temperature dependence of critical current can be deduced while n is between 1 and 2. In particular, the regular oscillating phenomena associated with the temperature dependence of resistivity with the application of microwave onto the region of weak-link have been observed. In essence, such interesting feature should be elucidated in advence in the studies of nonlinear-nonstationary dynamics of the Josephson effect.