TY - JOUR
T1 - Crystal structure of annealed and as-prepared HgBa2CaCu2O6+δ superconductors
AU - Huang, Q.
AU - Lynn, J. W.
AU - Meng, R. L.
AU - Chu, C. W.
N1 - Funding Information:
We would like to thank J. Stalick for her assistance with the calibration of the diffractometer, and N. Rosov, J.J. Rush and A. Santoro for helpful discussions and assistance. The research at the University of Houston is supported in part by the NSF, DMR 91-22043, USAFOSR grant No. F49620-93-1-0310, the State of Texas through the Texas Center for Su- perconductivity at the University of Houston, and the T.L.L. Temple Foundation.
PY - 1993/12/15
Y1 - 1993/12/15
N2 - Neutron profile refinements have been carried out on powders of as-prepared and oxygen annealed samples of the layered HgBa2CaCu2O6+δ (1212) cuprate superconductors. The crystal structure is tetragonal P4/mmm over the range of temperatures 10 K to 298 K investigated, with no structural transitions of any kind being detected. The extra oxygen that electrically dopes these materials is found to reside in the centered position of the Hg plane, and no other excess oxygen is present in these samples. In addition, we found no conclusive evidence for mixing of the Hg and Cu cations. In the as-prepared sample we found δ=0.22, while the oxygen content increased substantially to δ=0.35 with annealing. This extra oxygen had only a small effect on the superconductivity, broadening the transition somewhat and shifting Tc from 112 K to 120 K. The incorporation of extra oxygen also had the effect of constructing the lattice parameters by ∼ 0.1%. The overall behavior is similar to the single-layer Hg-1201 system.
AB - Neutron profile refinements have been carried out on powders of as-prepared and oxygen annealed samples of the layered HgBa2CaCu2O6+δ (1212) cuprate superconductors. The crystal structure is tetragonal P4/mmm over the range of temperatures 10 K to 298 K investigated, with no structural transitions of any kind being detected. The extra oxygen that electrically dopes these materials is found to reside in the centered position of the Hg plane, and no other excess oxygen is present in these samples. In addition, we found no conclusive evidence for mixing of the Hg and Cu cations. In the as-prepared sample we found δ=0.22, while the oxygen content increased substantially to δ=0.35 with annealing. This extra oxygen had only a small effect on the superconductivity, broadening the transition somewhat and shifting Tc from 112 K to 120 K. The incorporation of extra oxygen also had the effect of constructing the lattice parameters by ∼ 0.1%. The overall behavior is similar to the single-layer Hg-1201 system.
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U2 - 10.1016/0921-4534(93)90036-P
DO - 10.1016/0921-4534(93)90036-P
M3 - Article
AN - SCOPUS:0027883685
VL - 218
SP - 356
EP - 364
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
SN - 0921-4534
IS - 3-4
ER -