de.mpg.escidoc.pubman.appbase.FacesBean
English
 
Help Guide Disclaimer Contact us Login
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Crystal structure and cation stoichiometry of superconducting Tl<sub>2</sub>Ba<sub>2</sub>CuO<sub>6+δ</suB> single crystals

MPS-Authors
There are no MPG-Authors available
Locator
There are no locators available
Fulltext (public)
There are no public fulltexts available
Supplementary Material (public)
There is no public supplementary material available
Citation

Liu, R., Hughes, S., Angel, R., Hackwell, T., Mackenzie, A. P., & Edwards, P. (1992). Crystal structure and cation stoichiometry of superconducting Tl<sub>2</sub>Ba<sub>2</sub>CuO<sub>6+δ</suB> single crystals. Physica C-Superconductivity and its Applications, 198(3-4), 203-208. doi:10.1016/0921-4534(92)90192-F.


Cite as: http://hdl.handle.net/11858/00-001M-0000-0018-E7C1-B
Abstract
High quality single crystals of Tl2Ba2CuO6+delta have been obtained by a CuO self-flux method. The synthesized crystals have an average chemical composition of Tl1.85(4)Ba1.94(4)Cu1.15(2)O6+delta as determined by electron probe microanalysis (EPMA), suggesting a possible substitution of Cu for Tl. Single-crystal X-ray diffraction experiments and structure refinement show that the crystal exhibits tetragonal symmetry (space group I4/mmm), with lattice parameters a = 3.8608 (4) angstrom and c = 23.1332 (9) angstrom. Site occupancy refinements indicated completely occupied Ba and Cu sites within the structure, and a deficiency in the scattering power of the Tl site. The final structure refinement corresponds to a composition Tl1.87(2)Ba2Cu1.13(2)O6+delta, which is consistent with the EPMA results. The quality of the diffraction data allow Tl and O (which comprise the Tl2O2 layers) to be unambiguously assigned to split sites of the type xOz, as opposed to xxz sites. There is no evidence for long-range ordering of the displacements of the atoms in the T1202 layers of this crystal. The as-grown single crystals have a superconducting transition temperature, T(c), of 12.4 K. The T(c) of the as-grown crystals could be enhanced via low temperature annealing in a reducing atmosphere.