Superconducting NdCeCuO Bicrystal Grain Boundary Josephson Junctions

TL;DR

This study investigates the electrical transport in NdCeCuO bicrystal grain boundary Josephson junctions, revealing that their properties are similar to hole-doped high-temperature superconductors and are largely unaffected by the order parameter symmetry.

Contribution

It provides new insights into the transport properties of electron-doped cuprate GBJs and their similarity to hole-doped counterparts, challenging assumptions about the influence of order parameter symmetry.

Findings

Critical current density decreases with misorientation angle.

IcRn product scales with the square root of Jc.

Superconducting properties are similar to hole-doped HTS GBJs.

Abstract

We have studied the electric transport properties of symmetrical [001] tilt NdCeCuO bicrystal grain boundary Josephson junctions (GBJs) fabricated on SrTiO bicrystal substrates with misorientation angles of 24 and 36.8 degree. The superconducting properties of the NdCeCuO-GBJs are similar to those of GBJs fabricated from the hole doped high temperature superconductors (HTS). The critical current density Jc decreases strongly with increasing misorientation angle. The products of the critical current Ic and the normal resistance Rn (about 0.1 mV at 4.2 K) are small compared to the gap voltage and fit well to the universal scaling law (IcRn is proportional to the square root of Jc) found for GBJs fabricated from the hole doped HTS. This suggests that the symmetry of the order parameter, which most likely is different for the electron and the hole doped HTS has little influence on the characteristic properties of symmetrical [001] tilt GBJs.