Superconductivity at 40 K in the oxygen-defect perovskites La(2-x)Sr(x)CuO(4-y)
Abstract
Structural, magnetic, and electronic properties of compounds in the series La(2-x)Sr(x)CuO(4-y) for x = 0.05-1.1, with Delta-x = 0.025, were studied. Resistance, susceptibility, Meissner, and shielding measurements have revealed superconductivity among several members of the series. For x = 0.15, the transition temperature T(c), measured at the midpoint of the resistive transition, is a maximum at 39.3 K with a width of 2 K. At other compositions the transition is broader and occurs at a lower temperature. Annealing the x = 0.15 sample in oxygen at 500 C increases T(c) to 40.3 K, while annealing at the same temperature under vacuum suppresses the superconductivity. These changes in oxygen content and T(c) are reversible.
- Publication:
-
Science
- Pub Date:
- March 1987
- DOI:
- 10.1126/science.235.4794.1373
- Bibcode:
- 1987Sci...235.1373T
- Keywords:
-
- Lanthanum Compounds;
- Metal Oxides;
- Perovskites;
- Superconductivity;
- Transition Temperature;
- Magnetic Permeability;
- Magnetic Properties;
- Resistance;
- Solid-State Physics