Spurious magnetism in high-Tc superconductor

Abstract

One challenge in condensed-matter physics is to unravel the interplay between magnetism and superconductivity in copper oxides with a high critical temperature (Tc). Kang et al. claim to have revealed a quantum phase transition from the superconducting to an antiferromagnetic state in the electron-doped material Nd2-xCexCuO4 (NCCO) based on the observation of magnetic-field-induced neutron scattering intensity at (1/2,1/2,0), (1/2,0,0), and related reflections. Here we argue that the observed magnetic intensity is due to a secondary phase of (Nd,Ce)2O3. We therefore contend that the effect is spurious and not intrinsic to superconducting NCCO.

Published in Nature 426, 139 (2003). Comment on "Antiferromagnetic order as the competing ground state in electron-doped Nd1.85Ce0.15CuO4", H.J. Kang et al., Nature 423, 522 (2003)