Low-temperature behavior of oxygen ordering in YBa2Cu3O6+2c: calculation of length of O (1)-Cu (1)-O (1) chains at T < 100 K

✍ Scribed by V.M. Matic

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 690 KB
• Volume: 211
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(93)90744-b

✦ Synopsis

Oxygen ordering in the basal plane of YBa2Cu306+2c is investigated in terms of the two-dimensional Ising model with the repulsive nearest-neighbor O-O bond ( Vl ) and the second-neighbor O-O bond (I/3), while O-O interaction through Cu (//2 ) is attractive. The phase diagram is calculated using the modified cluster field model (MCFM) for values of interactions obtained by the linear muffin-tin orbital (LMTO) first-principle calculations. The analytic closed-form expression, based on the cluster variation method (CVM), for the length ofO( 1 )-Cu( 1 )-O( 1 ) chains I at arbitrary low temperatures, is derived and compared with MCFM calculations for T> 100 K. The agreement with the MCFM calculations is excellent. We found that the slope of In(l) versus inverse temperature plot practically equals 21 V21 for all values of oxygen content c and temperatures below room temperature.