Hole concentration, Hall number, and disorder in compensation doped NdBa2Cu3Oy
Abstract
The compensation doped systems Nd(1+x)-cCacBa2-xCu3Oy and Nd1+xBa2-xCu3-zZnzOy are studied to elucidate both the dependence of Tc on the CuO plane hole concentration and the effect of disorder on the planes. Nd substitution for Ba reduces Tc and the plane holes. Ca substitution compensates for Nd, raising Tc and the plane holes. Zn has a small effect on the hole concentration. More importantly, Zn causes disorder on the CuO planes, suppressing Tc. The choice of these Nd systems is very important, because, contrary to the YBa2Cu3-xZnxOy based systems, the Hall number can be unambiguously interpreted and is in good agreement with the plane hole concentration derived from chemical analysis and the method of Tokura et al. for dividing the total holes into mobile plane holes and local chain holes. © 1989.