Spurious magnetism in high-Tc superconductor

TL;DR

This paper challenges previous claims of a quantum phase transition in electron-doped cuprate superconductors, arguing that observed magnetic signals are due to a secondary phase rather than intrinsic properties.

Contribution

It provides evidence that the magnetic signals attributed to a phase transition are actually caused by a secondary phase, clarifying the true nature of magnetism in NCCO.

Findings

Magnetic signals are due to a secondary phase, not intrinsic to NCCO.

Reinterpretation of neutron scattering data in electron-doped cuprates.

Spurious effects can mimic genuine magnetic transitions.

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.