X-ray single crystal analysis of HgBa2Ca2Cu3O8+δ and influence of oxygen stoichiometry on the superconducting properties

✍ Scribed by A. Bertinotti; D. Colson; J. Hammann; J.-F. Marucco; D. Luzet; A. Pinatel; V. Viallet

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 634 KB
• Volume: 250
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(95)00375-4

✦ Synopsis

X-ray diffraction analyses of good-quality single crystals of HgBa2Ca2Cu3Os+8, synthetized by a closed-vessel technique at low pressure, have lead to more definite results with respect to previous structural studies. Samples with T c = 135 K showed a Cu occupancy of 16.1% on the Hg site at the origin of the unit cell. Excess oxygen appears to be present only in the basal plane at the interstitial site 1, ½, 0 with an occupancy 6 = 0.190 + 0.015. This compound has the shortest copper oxygen apical distance within the mercury family (2.696(3) A) together with an almost complete planarity of the CuO 2 planes. Variations in the excess oxygen content upon different heat treatments were analyzed by thermogravimetry and magnetic-susceptibility measurements. A correlation between ~ and T c could be derived, showing in particular that superconductivity exists down to a very low interstitial oxygen content.