An approach has been made to deduce the second moment contribution of the planar Cu NMR line from indirect nuclear couplings, using the middle plane sites of the trilayer superconductor, Hg0.8Re0.2Ba2Ca2Cu3O8(Tc=126K). We find that T1 fluctuations of neighboring nuclear spins in the plane are the dominant causes of the spin-echo decay observed in the present case of an external field perpendicular to the c axis. Taking account of this effect in the analysis, the second moment is deduced. From the T dependences of the T1 and second moment thus obtained, we find the dynamical exponent, z=2. The present result indicates that the boundary of z crossing from 2 (overdamped regime) to 1 (quantum critical regime) may be shifted more closely to the antiferromagnetic phase than previously assumed. It is also shown that the pseudogap is not a specific feature to the z=1 region.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - 1999|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics