Abstract
A small decrease in of 0.3 K to 0.5 K is observed when as much as 90% of the in is substituted with . This result is consistent with our observation that there is an oxygen isotope effect in , but in contrast with previous reports that there is no isotope effect for . This new result suggests that phonons play an important role in the electron-pairing mechanism in .
- Received 29 July 1987
DOI:https://doi.org/10.1103/PhysRevLett.59.1236
©1987 American Physical Society