Manifestation of Anisotropy in Melting Systematics of Rba2Cu3O7-delta (R= lanthandies)

Published

March 26, 2007

Author(s)

H Su, D O. Welch, Winnie Wong-Ng, Lawrence P. Cook, Z Yang

Abstract

The conventional Debye temperature, customarily estimated using an isotropic approximation, fails to account for the trend of melting temperatures for the high Tc superconductors, RBa2Cu3O7-d (R-123), as a function of the ionic radius of R3+, or r(R3+). We overcome this problem by calculating the improved Debye temperatures using the mean sound velocity along the c-axis of R-123 that features an anisotropic layered structure. Using this improved Debye temperature, the trend of the derived melting temperatures based on the Lindermann law matches well with the experimental data. This trend is also confirmed by comparing the theoretical and experimental Raman active modes corresponding to the Cu-O (plane-copper and apical-oxygen) and Ba-O (in-plane) bonds in the R-123 series. It is concluded that internal strains arising from the complex R-123 structure have significantly anisotropic effects on the melting of these compounds.

Citation

Applied Physics Letters

Volume

91

Pub Type

Journals

Keywords

Debye temperature, effect of structural anisotropy on, internal strain on melting, Linderman law, melting trend of RBa2Cu3O7-x

Citation

Su, H. , Welch, D. , Wong-Ng, W. , Cook, L. and Yang, Z. (2007), Manifestation of Anisotropy in Melting Systematics of Rba₂Cu₃O_7-delta (R= lanthandies), Applied Physics Letters (Accessed October 20, 2025)