Zn-substituted YBa2Cu4O8 high-temperature superconductors have been probed by Y89 nuclear magnetic resonance (NMR), susceptibility, and thermopower measurements. With Y89 NMR we have been able to study the gap in the spin density of states using the real part of the spin susceptibility determined from the Knight shift as Zn is progressively substituted onto the plane copper site. Zn substitution results in a rapid decrease in Tc with a negligible decrease in the spin-gap energy and an inhomogeneous filling in of the gap in spin density of states.
ASJC Scopus subject areas
- Condensed Matter Physics