HALL-EFFECT STUDY OF BULK YBA2CU3-XFEXOY LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.2, 6-LESS-THAN-Y-LESS-THAN-7)

We report systematic measurements of the resistivity and of the Hall c oefficient R(H) of bulk YBa2Cu3-xFexOy by varying both the iron doping and the oxygen concentration and for temperatures ranging from 100 to 250 K. The Hall number n(cell)(at 100 and 200 K) decreases linearly w ith decreasing y for all x and exponentially upon Fe doping. The tempe rature dependence of n(cell) is strongly suppressed upon removing hole s from the system either by increasing the amount of iron doping or by deoxygenation. The dependence of n(cell) on temperature and on doping as well as the relation between dn(cell)/dT - T(c) and T(c) - n(cell) are also discussed. Finally, we discuss our results in the context of the cottheta(H) vs T2 variation.