臺灣博碩士論文加值系統

厚膜是高溫超導重要的研究領域與可能的應用方向之一，本文即利用
SrCaCu2O4、SrCaCu4O6 (鉍系高溫超導體的先驅產物(precusor)) 和銀片
當基板，以網板印刷法分別在其表面絹印(Bi2O3+PbO) 的混合粉末以及添
加鉍鉛玻璃的BSCCO厚膜材料，然後根據DTA曲線在700∼900℃之間燒製成
鉍鍶鈣銅氧(BSCCO)超導厚膜o從X-ray繞射顯示以SrCaCu4O6為基板所燒製
而成的BSCCO膜，皆為 2201伴隨著少量的2212相; 而以SrCaCu2O4 為基板
的BSCCO膜卻顯示著 2212 相結構，但經由R-T 和χa.c. 的量測卻可明顯
看出兩個超導相，分別為Tc=110K的 2223高溫相以及 Tc=80K 的2212相結
構，但因主成分為 2212相，故其Tc(zero)皆在80K左右o 由於Jc(2223)<
Jc(2212)，在應用上，含有2223 的混合相可能會影響到其超導性，所以
在純化方面仍有待改善 o 另外在銀基板上，我們製得厚膜之厚度約為50
um，Tc約為80K之2212相，其在銀基板上不僅呈現良好的附著性，而且還
具有(00l) 的擇向性o 由於鉍系超導體中， 過量的氧含量會影響其超導
性，因此我們將成長後之厚膜，再置於600℃的氮氣氛中維持2 小時，作
退火(annealing)處理，所獲得之樣品經R-T，SQUID以及X-ray量測，可得
到Tc=85K，c 軸長為30.91 A 且鍵結情形良好之純2212相結構o 經由EDS
分析得知厚膜樣品之化學組成為 (Bi,Pb)2(Sr,Ca)3Cu2Ox o

The Bi-Sr-Ca-Cu-O superconducting thick films were grown by
printing appropriate mixtures of Bi2O3+PbO and the BSCCO films
with (Bi2O3+PbO)-doped on substrates of SrCaCu2O4 , SrCaCu4O6
and Ag separately, and then followed by a diffusion process at
700-900℃ according to the DTA data. The results from XRD
reveal that the BSCCO films by using SrCaCu4O6 substrate are
(2201) accompany with a little (2212) phase and for those by
using SrCaCu2O4 substrate are (2212) phases dominantly. Both
superconducting BSCCO films by R-T andχa.c.measurements show a
mixed phases of (2223) and (2212) with Tc(onset)=110K and Tc(
zero)=80K. The thickness of the BSCCO films are about 50um.
They have shown to possess Tc=80K by SQUID and R-T
measurements on Ag substrate. BSCCO films have shown a
preferred orientation by XRD measurements. Because the excess
oxygen causes degradation of the superconducting parameters of
BSCCO thick films. Thereore , the grown thick films were
annealed in N2 atomphere at 600℃ for 2 hr and cooled to room
temperature at a rate of 500℃/hr. Tc of the as-grown thick
films have enhanced up to 85k by the R-T measurement. In
addition, the chemical composition of these samples as
determined by EDS analysis are (Bi,Pb)2(Sr,Ca)3Cu2Ox.