Nonstoichiometry and decomposition of La1+zBa2−zCu3Oy and La4BaCu5O13−w

✍ Scribed by T.B. Lindemer; E.D. Specht; C.S. MacDougall; G.M. Taylor; S.L. Pye

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 984 KB
• Volume: 216
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(93)90639-8

✦ Synopsis

The temperature (T, K) and oxygen pressure (po,, Pa) dependence of oxygen content in La,+,Ba2_,Cus0, ( 123 #) and La,BaCu~O,~_, (415) *were determined over the ranges 10 Pa to 0.1 MPa Or, 0.0<&0.7 and 523sTs 1223 K. The data for each phase were correlated with chemical thermodynamic representations. For Lal+Bal_zCulO,, the T-z-y-p,, behavior was modeled as a solution of LaBarCu,O,_, and 415. The experimental data demonstrated 7 -x values < 6 at high temperatures, while they exceeded 6.99 only at temperatures approaching ambient at 0.1 MPa Or. These two characteristics are not known to occur in the other lanthanide and Y analogues. The T-l-p, dependence of high-temperature decomposition was determined and, in conjunction with X-ray analysis, permitted construction of the phase diagram lying between LaBa2Cu10,_, and 415. Effects of residual carbonate content were also determined.