ADDITIVE QUASI-PARTICLE AND VORTEX HALL CONDUCTIVITIES IN LA2-XSRXCUO4 AND UNTWINNED YBA2CU3O6.93

The flux-flow Hall conductivity σxy in untwinned YBa2Cu3O6.93 (YBCO) is determined from Hall and resistivity measurements with the current applied along the a and the b axes. We show that sign reversal results from competition between a positive quasiparticle current (∼H) and a negative vortex-motion term (∼1/H). The Hall drag coefficient in YBCO is measured to be α(T)=-4.4×10-8(1-T/Tc) N s/m2 (75<T<93 K). In single-crystal La2-xSrxCuO4, a similar decomposition into quasiparticle and vortex currents (both positive) is possible even though σxy shows no sign reversal. © 1995 The American Physical Society.