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NIST High Temp. Superconducting Materials (HTS) Database:

NIST Standard Reference Database 62

Last Update to Data Content: 1996

DOI: https://doi.org/10.18434/T4KP8J

Bibliographic Information

Title: High-Pressure Synthesis of the Members with n = 1 to 6 of the New Superconducting Family HgBa2Can-1CunO2n+2+δ
Author(s): S.M. Loureiro, E.V. Antipov, E.T. Alexandre, E. Kopnin, M.F. Gorius, B. Souletie, M. Perroux, R. Argoud, et al.
Publication: Physica C Volume: 235 Issue: Not Available Year: 1994 Page(s): 905-906
Editor(s): Not Available
Publisher: Elsevier Science Publishers B.V.
Language: English
Notes: et al.= O. Gheorghe, J.L. Tholence, and J.J. Capponi
Keywords: Material Specification, Crystallography, Critical Temperature

Materials and Properties

[Hg-Ba-Ca-Cu-O]
Material Specification for ; [Hg-Ba-Ca-Cu-O] Process: Solid State Reaction
Notes: The authors cite M. Contre, French Patent, 1.457690, and summarize the procedure as follows. "We used a "belt" type apparatus... The sample holder is a platinum or gold capsule made of two small tubes closed at one end and housed one inside the other. (These) form a closed capsule, 6 mm diameter and 6 mm length, which is impervious when squeezed in the pressure cell. ... The pressure cell is made of pyrophyllite, teflon, soft alumina, and a graphite tube for heating. The starting material is introduced in the capsule inside a glove box, and the sample is immediately placed in the "belt". For the sintering process the temperature is raised after establishing the pressure. At the end of the treatment, which takes 1-2 h, the sample is quenched by switching off the heating power and the pressure is released. A 350 mg sample is prepared in each run. ... The starting material used in the high pressure experiments is a mixture of HgO with a precursor. Precursors are synthesized by solid state reaction of nitrates at increasing temperatures. The final annealing conditions are 925 °C (for) 72 h with intermediate grindings. The last treatment is made under dry and decarbonated oxygen. ... X-ray examination of the precursors showed mainly a mixture of two or more of the following compounds: BaCuO2, CaO, Ba2Cu3O5+x, and Ba2CuO3+x."
Formula: HgBa2Can-1CunO2n+2+x
Informal Name:
Chemical Family: Hg-Ba-Ca-Cu-O
Chemical Class: Oxide
Structure Type: Polycrystalline
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:

Crystallography for ; [Hg-Ba-Ca-Cu-O]
Crystal System: Tetragonal
Formula Units per Cell:
Space Group:
Cell Parameters
Phase () Purity (%) Temp K a Å b Å c Å
Hg:1201 95 296 3.8713 -- 9.4968
Hg:1212 95 296 3.8526 -- 12.6367
Hg:1223 98 296 3.8502 -- 15.7829
Hg:1234 90 296 3.8503 -- 18.911
Hg:1245 80 296 3.8521 -- 22.100
Hg:1256 85 296 3.8500 -- 25.243
Measurement Method: Neutron diffraction
The related paper, J.J. Capponi et al., Physica C, Vol. 235-240 (1994) 146-149, indicates that the cell parameters were determined by neutron diffraction refinements.

Cautions: Unevaluated Data
Critical Temperature for ; [Hg-Ba-Ca-Cu-O]
Phase () Purity (%) Critical Temperature (K)
Hg:1201 95 92
Hg:1212 95 126
Hg:1223 98 135
Hg:1234 90 126
Hg:1245 80 112
Hg:1256 85 106
Measurement Method: Unknown Tc method
No measurement details were noted.

Cautions: Unevaluated Data