Effect of mixing three RE elements (Nd, Eu, Gd) on the REBa 2Cu 3O 7− x phase in RE–cuprate high- Tc superconductors

Abstract

The relationship between average rare earth (RE) radius and the peritectic decomposition temperature was investigated through the differential thermal analysis (DTA) of mixed rare earth (Nd, Eu, Gd) barium cuprates. The peritectic decomposition temperature ( T p) of compositions within the `ternary' (Nd x Eu y Gd z )Ba 2Cu 3O 7− δ ( x+ y+ z=1), whilst maintaining a constant average RE cationic radius of 1.076 Å, was observed to be uniform. Analysis of the processed materials using powder X-ray diffraction showed the lattice parameters to be uniform also with such compositional changes. These results indicate uniform mixing of the RE elements in the RE123 phase.