Crystallographic evolution
| Autor: | S.-W. Cheong, Bertram Batlogg, L. W. Rupp, H. Y. Hwang, Z. Tan, George H. Kwei, A. S. Cooper |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
Superconductivity
Valence (chemistry) Materials science Neutron diffraction Energy Engineering and Power Technology Crystal structure Condensed Matter Physics Electronic Optical and Magnetic Materials Ion Metal Crystallography visual_art Vacancy defect X-ray crystallography visual_art.visual_art_medium Electrical and Electronic Engineering |
| Zdroj: | Physica C: Superconductivity. 192:362-371 |
| ISSN: | 0921-4534 |
| DOI: | 10.1016/0921-4534(92)90842-z |
| Popis: | In our comprehensive crystallographic investigation of the quasi-binary Pr2CuO4-Sr2CuO3 system, we observe the structural evolution T ′→ T ∗ → T → Sr 2 CuO 3 with increasing Sr substitution in P Pr2−xSrxCuO4−δ, that is distinctly different from the behavior in Sr-dopped La2CuO4 or Nd2CuO4. From the results of structural refinement using neutron powder diffraction and valence study from PrL3 X-ray absorption, we find that the stabilization of the T∗ phase in Pr1.6Sr0.4CuO4 is associated with the preferential occupation of large Sr ions in the T-type half unit cell and the presence of Pr ions in the T'-type half unit cell having an average valence larger than 3+. Furthermore, the presence of large in-plane oxygen deficiency is related to the stabilization of the T structure in Pr1.0Sr1.0CuO3.6. Formal Cu valence in the T∗ or T compound, deduced from an oxygen stoichiometry study using thermogravimetric analysis and neutron structural refinement, is larger than 2+; however, neither superconductivity nor metallic behavior is observed. |
| Databáze: | OpenAIRE |
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