EXPERIMENTAL TEST OF THE T2 LAW FOR THE HALL ANGLE FROM TC TO 500-K IN OXYGEN-REDUCED YBA2CU3O6+X CRYSTALS

In both "90-K" and "60-K" YBa2Cu3O6+x crystals, we find that the T2 law for the Hall angle, measured with field H parallel-to c, remains valid for temperatures T between T(c) and 500 K. The persistence of power-law behavior over this wide range is not affected by oxygen reduction. In contrast to this anomalous behavior, the Hall coefficient observed with H perpendicular-to c is negative and temperature independent. Measurements of the in-plane resistivity rho(xx) to 500 K disclose the existence of a kink temperature T(K)(approximately 320 K) that separates a high-temperature power-law regime from a low-temperature region in which rho(xx) displays significant curvature.