๐”– Bobbio Scriptorium
โœฆ   LIBER   โœฆ

Synthesis of Tl2CanBa2Cun+1O6+2n (n=1, 2) from stoichiometric reactant mixtures

โœ Scribed by Nae-Lih Wu; Yeong Der Yao; Sern-Nan Lee; S-Yen Wong; Eli Ruckenstein


Book ID
103943469
Publisher
Elsevier Science
Year
1989
Tongue
English
Weight
748 KB
Volume
161
Category
Article
ISSN
0921-4534

No coin nor oath required. For personal study only.

โœฆ Synopsis


New powder synthesis methods have been developed for the preparation of single-phase TI2CaBa2Cu2Oa (the 2122 compound) and T12Ca2Ba2Cu3Oto (the 2223 compound) powders from stoichiometric reactant mixtures. The 2122 compound was prepared from a stoichiometric mixture of T1203, CuO and CaBa2CuO4, while the 2223 compound was prepared from the same mixture hut with additional CaO and CuO to match the correct (TI:Ca:Ba:Cu = 2:2:2:3 ) stoichiometry. For the 2122 compound, XRD single-phase samples with zero-resistivity temperatures (Tยข.ze~o) above 100 K were obtained by using a one-step calcination at 830ยฐC for a period between 6 and 23 h. A maximum of To.zero of 116 K was obtained for 14h of calcination. For the 2223 compound, XRD single-phase samples with Tยข.z,~o between 110 and 118 K were obtained by employing a two-step calcination procedure consisting of a first calcination at 830ยฐC for 5 h and a second calcination at 870ยฐC for a period between 2 and 6 h. Both the 2122 and 2223 samples thus prepared exhibit sharp superconducting transitions and typically have a saturation Meissner effect of about 20% of ( -1/4n) under a field of 20 G. Powder melting is completely eliminated during the preparation of the 2122 compound and much reduced, by employing the pre-calcination step, during the preparation of the 2223 compound. Compared with the conventional method, the new methods require less stringent calcination conditions, and hence allow for a better process control of the synthesis of T12CanBa2Cun+106+n superconducting powders.


๐Ÿ“œ SIMILAR VOLUMES


Preparation and superconducting properti
โœ T. Fujiwara; Y. Koike; M. Inaba; T. Noji; M. Kato; Y. Saito ๐Ÿ“‚ Article ๐Ÿ“… 1994 ๐Ÿ› Elsevier Science ๐ŸŒ English โš– 158 KB

We have succeeded in preparing a new single-phase of Pb~Sr~(Hm-.Ca~)n-,Cu,~+,02,,.~ with n = 3 (Pb-3223 phase) and also a single phase of n = 2 (Pb-3212 phase) by thin film processing. The thin films, oriented along the c-axis, have been prepared on MgO(lO0) substrates by rfsputtering at room temper