Current dependent angular magnetoresistance in strongly Pr-doped Y Ba2Cu3O7-δ single crystal

We report a strong dependence of the angular magnetoresistance (AMR) on the current density in Y Ba2Cu3O7-δ single crystal above the critical temperature Tc = 13 K for any applied field up to 14 T. We estimated the current dependence from the angular dependence of the top resistance Rtop, as measured on the face where the current is applied, and the bottom resistance Rbot as measured on the opposite face. At any temperature, both below and above Tc, Rtop decreases as the field becomes parallel to the current and ab-plane with an angle dependence that suggests an important contribution arising from the vortex flow. Rbot evolves from a monotonic to nonmonotonic angle dependence with three minima and two maxima in the angle range 0 - 180 deg. as the temperature increases. For less Pr-doped samples, Y0.58Pr0.42Ba2Cu3O7-δ (Tc = 39 K) and Y0.68rP0.32Ba2Cu3O7-δ (Tc = 55 K), where the interplane resistivity is much lower, both Rtop and Rbot follow the same monotonic angle dependence in all temperature and field range.