Diamagnetic shielding and Meissner effect in the high T c superconductor Sr 0.2La 1.8CuO 4
Abstract
SQUID susceptibility measurements of the high T c superconductor Sr 0.2La 1.8CuO 4, with a 40 K resistive onset, are reported for fields from 1 μT to 4.5 T (10 mG to 45 kG). Data show an average lower critical field of 30 mT at 5 K, but with nonlinearities appearing as low as 100 μT. Zero field cooling and subsequent application of a field shows a diamagnetic shielding effect reaching 100% in the lowest fields with a 37 K onset and 31 K midpoint. The observed Meissner effect in single phase material exceeds 40% but decreases with oxygen annealing even though T c increases.
- Publication:
-
Solid State Communications
- Pub Date:
- May 1987
- DOI:
- 10.1016/0038-1098(87)90990-2
- Bibcode:
- 1987SSCom..62..323M