Abstract
We have studied the effect of isotopic substitution on the superconducting Tc in the 90-K superconductors Ba2YCu3O7 and Ba2EuCu3O7 by replacing O16 with the heavier isotope O18. Samples with approximately 75% of the O16 replaced by O18 were prepared by gas-phase ion exchange. In these samples the phonon frequencies, measured by Raman spectroscopy, are reduced by the expected 4%. The transition temperatures, however, are found to change by less than 0.2%. This change in Tc is much less than that expected for strongly coupled phonon-mediated superconductivity.
Original language | English (US) |
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Pages (from-to) | 2333-2336 |
Number of pages | 4 |
Journal | Physical review letters |
Volume | 58 |
Issue number | 22 |
DOIs | |
State | Published - 1987 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- General Physics and Astronomy