Starting from high quality Nd1.85Ce0.15CuO4 polycrystalline samples with a Tc of 24K, we have exchanged ∼85% of 16O by 18O. The magnetically measured Tc was found to change by less than 0.1K, equivalent to an oxygen-isotope exponent 0α≤0.05. Thus, the isotope effect is small for all classes of cuprate superconductors when Tc is optimized, irrespective of CuO coordination and conduction type.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering