Vibrational properties and atomic Debye temperatures for YBa2Cu3O7 from neutron powder diffraction

✍ Scribed by George H. Kwei; A.C. Lawson; W.L. Hults; James L. Smith

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 575 KB
• Volume: 175
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(91)90274-3

✦ Synopsis

Neutron powder diffraction data taken at twelve sample temperatures have been used to determine both isotropic and anisotropic thermal parameters for atoms in YBa2Cu307. At fit of these parameters to a Debye-Waller model in turn yields the corresponding isotropic and anisotropic Debye-Waller temperatures. The anisotropic thermal parameters for the Y, Ba and the planar Cu(2) and 0(2) atoms all exhibit a stronger temperature dependence, and therefore a lower Debye-Waller temperature, for motion along the c-axis; in addition, the chain O( 1 ) atoms show a similar strong temperature dependence for motion perpendicular to the chains. No discontinuities in the thermal parameters, suggestive of possible structural changes or phonon anomalies near Tc are observed.