The 17O and 63Cu Knight shifts which are coupled to the spin susceptibility have been measured in the CuO2 plane and the CuO chain in the high-Tc superconductor YBa2Cu4O8. The shifts in the plane decrease with decreasing temperature, with small anomalies at Tc. In the chain, however, the shifts are temperature-independent in the normal state and those associated with the spin susceptibility along the Cu-O bonding decrease distinctly below Tc. Noting that the T-dependent susceptibility is dominated by the planar Cu2+, the hyperfine fields at Cu and O were estimated to be Hab(Cu2)=(185±10) kOe/μB and Hc(O 2,3)=(85±8)kOem/μB, in agreement with YBa2Cu3O7.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering