Low dimensional crystallographic motifs have long been associated with desirable physical properties. The confinement of electrons to low dimensions is thought to enhance quantum fluctuations and may promote correlated phenomena. Here, using the antagonistic pair concept, we add Y to the immiscible Co-Ag pair to discover Y4Co3Ag. This compound adopts a monoclinic I2/m structure consisting of Y channels that are filled by one-dimensional zigzag and hexagonal Co chains, which extend along the crystallographic b-axis with no nearest neighbor contacts between Co and Ag atoms. Transport, magnetic, and specific heat measurements reveal that Y4Co3Ag orders antiferromagnetically at TN=14.9 K with an effective magnetic moment μeff = 1.4 μB/Co. Specific heat measurements show only a small entropy loss on the order of 0.1Rln2 associated with magnetic order, and magnetization isotherms, in DC fields up to 70 kOe at 1.8 K and in pulsed fields up to 600 kOe at 500 mK, indicate a small ordered moment of less than 0.2 μB/Co. Taken together, our results imply the presence of small, itinerant moments and strong fluctuations in Y4Co3Ag, suggesting that Y4Co3Ag may be a promising candidate material to investigate itinerant magnetic interactions in a quasi-one dimensional system.
@article{arxiv.2605.15495,
title = {Itinerant antiferromagnetism in the antagonistic pair compound Y$_4$Co$_3$Ag},
author = {Rafaela F. S. Penacchio and Nao Furukawa and Joanna M. Blawat and John Singleton and Zhouqi Li and Raquel A. Ribeiro and Sérgio L. Morelhão and Sergey L. Bud'ko and Paul C. Canfield and Tyler J. Slade},
journal= {arXiv preprint arXiv:2605.15495},
year = {2026}
}