Abstract
Oxygen isotope effects on and the Meissner fraction f have been investigated in fine-grained, decoupled with x=0.105, 0.110, and 0.115. We find that these oxygen isotope effects are related to each other: d ln/d lnM≊d lnf/d lnM (where M is the mass of oxygen). We also show that the trapped flux due to intergrain weak-link and intragrain flux pinning is negligible in our samples, and that the Meissner fractions for the samples with the same isotope are nearly equal The observed large oxygen isotope effects on and the Meissner fraction can be explained as due to the oxygen-mass dependence of (effective mass of carriers). The results may suggest that the conducting carriers in the cuprate superconductors are of polaronic type.
- Received 1 March 1995
DOI:https://doi.org/10.1103/PhysRevB.52.6840
©1995 American Physical Society