Title: 補償塊材組成對含鉛鉈系高溫超導薄膜相形成之影響
Effects of the composition of compensating bulk on the phase formation of Pb-doped Tl-based high-Tc superconducting thin films
Authors: 倪中興
Nee, Chong-Sine
莊振益
Jenh-Yih Juang
電子物理系所
Keywords: 鉈系超導薄膜;相;直流濺鍍;先驅膜;補償塊材;後續熱處理;Tl-based high-Tc superconductor;phase;DC sputtering;precursor film;compensating bulk;post annealing
Issue Date: 1996
Abstract: Tl1Ba2Ca2Cu3O9-δ相(Tl-1223相)因為具有:1.相鄰兩單位晶胞內的銅氧
層間距較短(~8.8A); 以及2.超導臨界溫度高(Tc~115-120K)的優點,故在
應用潛力與超導性質的研究上均引起相當大的注意。但是1223相比起其他
兩種鉈系高溫超導相,Tl-2223相和Tl-2212相,因為成長的條件範圍較為
狹窄,使得製作過程中環境條件的控制較為嚴苛。本實驗在Tl-Ba-Ca-Cu-
O系統中用鉛(Pb)取代部份的鉈(Tl),並改變退火時補償塊材的成份以及
熱處理條件來研究其對Tl-1223相形成之影響。以起始組成計量比接近
於1223的薄膜作為先驅膜,使用計量比為TBCCO-2223的塊材作為熱處理時
的補償,改變不同的氧氣壓力範圍,可以製作出接近純相的Tl-2223及
Tl-2212相薄膜。接著由製作出2223相的條件中,降低基板的溫度,製作
出純相的1212相的薄膜。然後藉著改變補償塊材中鉈的含量,找到了形
成1223相薄膜的條件。由實驗結果可以發現:除了氧氣分壓、基板的溫度
之外,補償塊材的組成成份,似乎是決定薄膜形成的超導相之最重要因數

Because of the following two merits: 1. the interlayer
distance between two groups of Cu-O trilayers within a unit cell
is short (~8.8A) compared to that of Tl-2223 and 2. the higher
superconducting critical temperature (Tc ~ 115-120K) compared to
that of YBCO. Tl1Ba2Ca2Cu3 O9-δ phase has been considered as a
material of high application potential. As a result, it has
attracted much attention recently. Nevertheless, the conditions
for the forma-tion of the Tl-1223 phase are much more
restrictive in comparison to that of the other two high-Tc
phases of Tl-based superconductors, 2212 and 2223. In this
study, we have tried to extend the formation conditions of
Tl-1223 phase by partially substituting Tl with Pb, and by
changing the composition of the compensating bulk material.Tl,
Pb)-2212 phase were produced in different ranges of O2 gas
pressure by using the precursor films with nominal
stoichiomentry of Tl:Ba:Ca:Cu = 1:2:2:3 and compensated by bulk
material with nominal stoichiomentry of Tl:Ba:Ca:Cu = 2:2:2:3
during annealing. By reducing the anneal temperature under
essentially the same conditions, the phase formed in the film
became mostly (Tl,Pb)-1212 phase. More interestingly, it was
found that the formation of (Tl,Pb)-1223 phase can be realized
only by changing the Tl content of the compensating bulks. The
results imply that the composition of the compensating bulk may
have played a major role in determining the phases formed during
post annealing process regardless of the starting composition of
the precursor films.
URI: http://140.113.39.130/cdrfb3/record/nctu/#NT850429014
http://hdl.handle.net/11536/62048
Appears in Collections:Thesis