Manifestation of Anisotropy in Melting Systematics of Rba2Cu3O7-delta (R= lanthandies)
H Su, D O. Welch, Winnie Wong-Ng, Lawrence P. Cook, Z Yang
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.
Applied Physics Letters
Debye temperature, effect of structural anisotropy on, internal strain on melting, Linderman law, melting trend of RBa2Cu3O7-x
, Welch, D.
, Wong-Ng, W.
, Cook, L.
and Yang, Z.
Manifestation of Anisotropy in Melting Systematics of Rba<sub>2</sub>Cu<sub>3</sub>O<sub>7-delta</sub> (R= lanthandies), Applied Physics Letters
(Accessed November 28, 2023)