# Anomalously large oxygen-ordering contribution to the thermal expansion of untwinned YBa2Cu3O6.95 single crystals: a glass-like transition near room temperature

Source: [Anomalously large oxygen-ordering contribution to the thermal expansion of untwinned YBa2Cu3O6.95 single crystals: a glass-like transition near room temperature](<https://www.sota2.com/research/paper/68fa24f32c2a3760193aafe3>)

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Data updated: 2025-10-24T09:41:56.116Z

Authors: Peter Nagel, Volker Pasler, Christoph Meingast, Alexandre I. Rykov, Setsuko Tajima

Published: 2000-01-20T10:29:54.000Z

## Abstract

We present high-resolution capacitance dilatometry studies from 5 - 500 K of untwinned YBa2Cu3Ox (Y123) single crystals for x ~ 6.95 and x = 7.0. Large contributions to the thermal expansivities due to O-ordering are found for x ~ 6.95, which disappear below a kinetic glass-like transition near room temperature. The kinetics at this glass transition is governed by an energy barrier of 0.98 +- 0.07 eV, in very good agreement with other O-ordering studies. Using thermodynamic arguments, we show that O-ordering in the Y123 system is particularly sensitive to uniaxial pressure (stress) along the chain axis and that the lack of well-ordered chains in Nd123 and La123 is most likely a consequence of a chemical-pressure effect.

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## Original sources and implementation

[Original paper](<https://arxiv.org/abs/cond-mat/0001287>)

[PDF](<https://arxiv.org/pdf/cond-mat/0001287.pdf>)