Longitudinal and transverse hall resistivities in high-T_c superconducting films and superlattices

The longitudinal and transverse, resistivities ρ_xx and ρ_xy, of high-T_c YBa₂Cu₃O_y films and (YBa₂Cu₃O_y/Y_xPr_1-xBa ₂Cu₃O_y)_n superlattices in a mixed state have been measured systematically to investigate the effects of magnetic field and flux pinning on the behaviors of ρ_xy and ρ_xx, the subscript n refers to the number of modulation layer in superlattices. Sign reversal of Hall coefficients is observed and depends on the pinning force. The power law, ρ_xy = Aρ_xx^β, persists in (YBa₂Cu₃O_y/Y_xPr_1-xBa ₂Cu₃O_y)_n superlattices with and without sign reversal.