SIGN REVERSALS IN THE VORTEX-STATE HALL-EFFECT IN Y-BA-CU-O - CORRELATIONS WITH THE NORMAL-STATE SEEBECK COEFFICIENT

Superconducting-Hall-effect R(H) transitions were measured on 11 YBa2C u3O7-delta epitaxial thin films grown under a range of electronic ''do ping'' conditions. The data reveal that the relative magnitude of the anomalous sign reversals in R(H) monotonically decrease with decreasin g carrier density and vanish below a threshold cutoff value. The sign reversals in R(H) are observed only in films having a negative normal- state Seebeck coefficient, and are correlated in magnitude. This sugge sts that the energy slope of the electronic density of states plays a role in the occurrence of these anomalies.