CHARACTERIZATION OF A SPLIT AXIAL-OXYGEN SITE IN TLBA2CA3CU4O11 BY EXTENDED X-RAY-ABSORPTION FINE-STRUCTURE SPECTROSCOPY

被引：40

作者：

ALLEN, PG ^{[1
]}

DELEON, JM ^{[1
]}

CONRADSON, SD ^{[1
]}

BISHOP, AR ^{[1
]}

机构：

[1] UNIV CALIF LOS ALAMOS SCI LAB,CONDENSED MATTER THEORY GRP,LOS ALAMOS,NM 87545

来源：

PHYSICAL REVIEW B | 1991年 / 44卷 / 17期

关键词：

D O I：

10.1103/PhysRevB.44.9480

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The Cu K-edge extended x-ray-absorption fine structure (EXAFS) of TlBa2Ca3Cu4O11 (T(c) = 118 K) is analyzed in the range 10 less-than-or-equal-to T less-than-or-equal-to 156 K. Nonlinear-least-squares fits to the EXAFS Cu-axial-oxygen contributions show the presence of two equally populated axial-oxygen sites at R1 = 2.57 angstrom and R2 = 2.74 angstrom for temperatures above T(c), and at 10 K. The corresponding Tl-axial-oxygen distances are 2.18 and 2.01 angstrom, which are similar to those found in other thallium superconducting phases. In a fluctuation region below T(c), (T = 100, 117 K), the separation between the two sites decreases to less than 0.10 angstrom. This effect is analogous to the one previously reported in YBa2Cu3O7, suggesting a similar coupling between elastic degrees of freedom and superconductivity. We note, however, that both the separation between the sites and the decrease in this separation within the fluctuation region are greater than in YBa2Cu3O7.

引用

页码：9480 / 9485

页数：6