Unusual Hall effect in superconducting (formula presented) films

We have investigated the temperature and magnetic field dependence of the Hall coefficient of two well-characterized superconducting (formula presented) films (formula presented) in both the normal and superconducting states. Our results show that the normal-state Hall coefficient (formula presented) is positive and increases with decreasing temperature, independent of the applied magnetic field (to 8 T). We find that (formula presented) and (formula presented) As the sample is cooled below (formula presented) (formula presented) decreases rapidly with temperature and changes sign before it reaches zero. The position and magnitude at which (formula presented) shows a minimum depends on the applied field.