The temperature spectra of the internal friction were determined in Zn-doped material, (Cu1-xZnx)3Ba2YO6, where x ranged from 0 to 0.1. Two thermally activated peaks near to the superconducting transition temperature were found to exhibit differing behaviours as a result of Zn-doping. The peak at 110K, P1, decreased rapidly with increasing x-value while the one at 120K, P2, exhibited no significant change. The relaxation mechanism of P1 was explained in terms of jumps of apical O atoms between off-centre positions which were produced by the Jahn-Teller effect.

Effect of Zinc Substitution on Internal Friction in YBCO Superconductors. A.Li, Y.N.Wang, X.N.Ying, Q.M.Zhang, W.M.Chen: Superconductor Science and Technology, 1999, 12[9], 645-8