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arXiv · 2501.15706

Anomalous temperature-dependent magnetization in the nearly collinear antiferromagnet Y$_2$Co$_3$

Yunshu Shi·Huibo Cao·Hung-Cheng Wu·Li Yin·Neil Harrison·David S. Parker·Tushar Bhowmick·Tessa McNamee·Fatemeh Safari·Sergey L. Budko·James C. Fettinger·Susan M. Kauzlarich·Peter Klavins·Dmitry Popov·Ravhi Kumar·Russell J. Hemley·Shanti Deemyad·Taku J. Sato·Paul. C. Canfield·Valentin Taufour
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Abstract

Y$_2$Co$_3$ is a newly discovered antiferromagnetic (AFM) compound with distorted kagome layers. Previous investigations via bulk magnetization measurements suggested a complex noncollinear magnetic behavior, with magnetic moments primarily anti-aligned along the $b$ axis and some canting towards the $ac$ plane. In this study, we report the magnetic structure of Y$_2$Co$_3$ to be an A-type AFM structure with ferromagnetic (FM) interactions within the distorted kagome plane and an interplane antiferromagnetic interaction, as determined by single-crystal neutron diffraction. The magnetic moments align along the $b$ axis, with minimal canting towards the $c$ axis, at odds with the previous interpretation of bulk magnetization measurements. The magnetic moments on the two distinct Co sites are [0, -0.68(3), 0] $\mu_B$ and [0, 1.25(4), 0.07(1)] $\mu_B$. We attribute the previously reported "noncollinear" behavior to the considerable temperature dependence of itinerant AFM exchange interactions, induced by thermal contraction along the $b$ axis. Additionally, our examination of lattice constants through pressure studies reveals compensating effects on FM and AFM interactions, resulting in negligible pressure dependence of $T_\textrm{N}$.

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Yunshu Shi, Huibo Cao, Hung-Cheng Wu, Li Yin, Neil Harrison, David S. Parker, Tushar Bhowmick, Tessa McNamee, Fatemeh Safari, Sergey L. Budko, James C. Fettinger, Susan M. Kauzlarich, Peter Klavins, Dmitry Popov, Ravhi Kumar, Russell J. Hemley, Shanti Deemyad, Taku J. Sato, Paul. C. Canfield, Valentin Taufour. 2025-01-26. Anomalous temperature-dependent magnetization in the nearly collinear antiferromagnet Y$_2$Co$_3$. https://doi.org/10.1103/physrevb.110.235159

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