Cu63(2) NMR linewidths in Zn-doped YBa2Cu3O7 exhibit a predominant component proportional to T-1 in the normal state. We attribute this result to spin-exchange scattering of carriers from localized moments associated with Zn impurities in the CuO2 planes. The estimated moment-carrier exchange, Jeff=20 meV, is more than an order of magnitude too small to account for the suppression of Tc in this system via Abrikosov-Gorkov pair breaking. A suggested alternative explanation is pair breaking by strong potential scattering from the Zn impurity sites which requires d-wave pairing.
|Number of pages||4|
|Journal||Physical Review B|
|State||Published - 1 Jan 1993|