NONLINEAR HALL RESISTIVITY IN YBA2CU3O7-DELTA FILMS NEAR THE VORTEX-GLASS TRANSITION

The Hall electric field E(y) is observed to be a strongly nonlinear fu nction of the current density J(x) in the vicinity of the vortex-glass transition of YBa2Cu3O7-delta films in a magnetic field. Much like th e longitudinal electric field E(x), E(y) appears to scale critically w ith J(x), with a Hall-related critical exponent lambda = 3.4 +/- 0.3. Furthermore, the Hall resistivity rho(xy) = E(y)/J(x) and the longitud inal resistivity rho(xx) = E(x)/J(x) are found to obey rho(xy) is-prop ortional-to rho(xx)2.0+/-0.2 over a wide range of current densities an d temperatures. The results quantitatively verify recent theoretical p redictions.