Nitride measurements reveal intertwined magnetic waves
A calcium-cobalt nitride develops an unusual magnetic pattern when cooled below about 54 K. Diffraction measurements favour two perpendicular waves while the crystal keeps its fourfold symmetry. The peer-reviewed experiment adds a nitrogen-containing material to research on competing magnetic interactions; the nearby spin-liquid state discussed by the authors remains a theoretical possibility.
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Cooling exposes magnetic modulation
Ca2CoN2, a nitride containing calcium, cobalt and nitrogen, acquired magnetic order below roughly 54 K in a peer-reviewed experiment released on 2 November. Neutrons scattered from the powder revealed a magnetic pattern whose spacing differs from a straightforward repeat of the crystal lattice. The proposed explanation combines magnetic waves running along perpendicular directions. Fourfold crystal symmetry persisted during cooling, providing another observation consistent with that interpretation.[1]
Competing interactions act within the cobalt lattice
The cobalt atoms occupy layers where different magnetic interactions compete. A further transition appeared near 30 K. Electronic calculations supported localized electrons, but represented the measured modulation through a simpler ordered arrangement because the full pattern was difficult to calculate. Thus the interpretation draws on both the diffraction results and approximations used in modelling the electrons.[1]
High-pressure synthesis yields an air-sensitive powder
High pressure was needed to prepare the black powder, which contained a small unidentified impurity and required protection from air. Changing its chemistry was discussed as a way to approach a predicted spin-liquid regime, where ordinary magnetic order is absent. The actual experiment observed ordered magnetism; chemical tuning towards the proposed alternative remains further work.[1]
