Anomalous magnetoresistance behavior of superconducting Nd2-xCexCuO4-y single crystal

Magnetoresistance measurements on a superconducting Nd2-xCexCuO4-y single crystal with Tc∼7 K were made with magnetic fields H applied parallel (H parallel c) and perpendicular (H perpendicular to c) to the tetragonal c-axis. For H parallel c, the resistive superconductive transition curves exhibit a double transition at low temperatures and high magnetic fields. This double resistive transition has a maximum near T∼1.1 K, followed by an extremely sharp transition into the superconducting state. For applied fields of 1 kOe, the resistivity first goes to zero, increases again to a finite value and then goes through a second transition. In this region, the resistivity exhibits non-ohmic behavior for low current densities and ohmic behavior for larger measuring currents. The resistivity for H perpendicular to c does not exhibit any anomalous behavior or a maximum for 0≤H≤60 kOe and 4 K≤T≤7 K. ((orig.))