Is RuO_2 an altermagnet? · revision history

Revision 2

Accepted · core change · record

Changes against revision 1:

Title · changed
Revision 1: Is RuO2 an altermagnet?
Revision 2: Is $\mathrm{RuO_2}$ an altermagnet?
Plain · changed
Revision 1: RuO2 was the first proposed metallic altermagnet, but muon and neutron measurements find no magnetic order in bulk crystals. Signals reported in thin films might come from surfaces or defects.
Revision 2: $\mathrm{RuO_2}$ was the first proposed metallic altermagnet, but muon and neutron measurements find no magnetic order in bulk crystals. Signals reported in thin films might come from surfaces or defects.
Precise · changed · core
Revision 1: Determine whether stoichiometric rutile RuO2 has collinear antiferromagnetic order with Ru moment above $1e-3\,\mu_B$, in bulk and in epitaxial films; if not, identify the origin of the anomalous Hall, spin-splitting torque and spin-resolved ARPES signals reported in films. An answer is a moment value or upper bound per sample type and a mechanism for the film signals.
Revision 2: Determine whether stoichiometric rutile $\mathrm{RuO_2}$ has collinear antiferromagnetic order with Ru moment above $10^{-3}\,\mu_B$, in bulk and in epitaxial films; if not, identify the origin of the anomalous Hall, spin-splitting torque and spin-resolved ARPES signals reported in films. An answer is a moment value or upper bound per sample type and a mechanism for the film signals.
Settled by
Muon, neutron and resonant x-ray measurements on the same films used for transport, combined with depth-resolved magnetic probes.
Kind
well-posed
Answer type
yes-no
References
(empty)
Literature status
contested
Status note · changed
Revision 1: Muon spin rotation and neutron diffraction (2024, arXiv:2405.10820) bound the bulk moment near $1e-4\,\mu_{\mathrm{B}}$ per Ru; a 2026 preprint (arXiv:2604.10659) attributes film signals to surface ferrimagnetism.
Revision 2: Muon spin rotation and neutron diffraction (2024, arXiv:2405.10820) bound the bulk moment near $10^{-4}\,\mu_{\mathrm{B}}$ per Ru; a 2026 preprint (arXiv:2604.10659) attributes film signals to surface ferrimagnetism.
Posed since
(empty)

Decisions