Magnetoresistivity of thin films of the electron-doped high-Tc superconductor Nd1.85Ce0.15CuO4±δ

Abstract

We report measurements of the magnetoresistance of Nd1.85Ce0.15CuO4±δ epitaxial thin films with varying oxygen content in magnetic fields H applied parallel (H∥c) and perpendicular (H⊥c) to the tetragonal c axis. We have observed critical scaling of the electrical resistivity that is consistent with a vortex-glass transition for a film with an optimum superconducting transition temperature Tc of ≊22 K and H∥c . The values of the zero-temperature upper critical field Hc2(0)=80 kOe and the in-plane zero-temperature coherence length ξab(0)=64 Å were obtained from an analysis of the fluctuation conductivity. For an overoxygenated film with Tc≊10 K, an anomaly develops with increasing field for H∥c and T≲2 K that is characterized by a minimum in the temperature dependence of the resistivity followed by a second resistive transition at a lower temperature, which is nearly independent of H. This behavior is similar to that previously observed in Nd2−xCexCuO4−δ single crystals and may be associated with the magnetic ordering of the Nd3+ ions. © 1996 The American Physical Society.

Source-reported materials — not catalogue approval

Similar papers