United States Patent | 5,294,600 |
Tanigaki, et. al. | Mar. 15, 1994 |
Inventors: | Tanigaki; Katsumi (Tokyo, JPX); Ebbesen; Thomas (Tokyo, JPX); Kuroshima; Sadanori (Tokyo, JPX); Mizuki; Junichiro (Tokyo, JPX). |
Assignee: | NEC Corporation (Tokyo, JPX). |
Appl. No.: | 907,627 |
Filed: | Jul. 2, 1992 |
Jul. 3, 1991 [JPX] | 3-163058 |
Jul. 3, 1991 [JPX] | 3-163059 |
Intl. Cl.: | C01B 31/00; H01L 39/12; |
U.S. Cl.: | 505/1.; 252/500.; |
Field of Search: | 1;800;775 |
5,223,479 | Jun., 1993 | McCauley | 505/775 |
Murphy et al. "New Superconducting Cuprate Perouskites" Phys. Rev. Let. vol. 58 pp. 1885-1890, May 1987.
Fleming et al. "Relation of structure and superconducting Trans. Temp. in A(3) C(60) " Nature vol. 352 Aug. 1991.
Hebard et al., "Superconductivity at 18 K in Potassium-doped C(60) ", Letters to Nature, vol. 350, No. 18, pp. 600-601, Apr. 18, 1991.
Rosseinsky et al., "Superconductivity at 28 K in Rb(x) C(60) ", Physical Review Letters, vol. 66, No. 21, pp. 2830-2832, May 27, 1991.
Holczer et al., "Alkali-Fulleride Superconductors: Synthesis, Composition, and Diamagnetic Shielding", Science, vol. 252, pp. 1154-1157, May 24, 1991.
Chen et al., "(Rb(x) K(1-x))(3) C(60) Superconductors: Formation of a Continuous Series of Solid Solutions", Science, vol. 253, Aug. 23, 1991, pp. 886-888.
Tanigaki et al., "Superconductivity at 33K in Cs(x) Rb(y) C(60) ", Nature, vol. 352, Jul. 18, 1991, pp. 222-223.
Kelty et al., "Superconductivity at 30K in caesium-doped C(60) ", Nature, vol. 352, Jul. 18, 1991, pp. 223-225.
A superconducting material higher in superconducting transition temperature and superconducting volume ratio than any conventional one is provided, which comprises a fullerene doped with rubidium and cesium. This fullerene system superconducting material makes it possible to improve both the superconducting transition temperature and superconducting volume ratio by having rubidium and cesium doped thereinto compared with any conventional fullerene systems. If the chemical composition of this super conducting material is expressed as Rb(x) Cs(y) C(n), x and y are arbitrary if an equation x+y=3 is satisfied, preferable to be x=2 and y=1, further preferable to be x=1 and y=s. The superconducting transition temperature Tc and superconducting volume ratio when x=1 and y=2 or x=2 and y=1 are superior to those when x=3 and y=0 or x=0 and y=3, respectively.