Document Type

Article

Abstract

Complex magnetic materials are extremely attractive for revealing unconventional spin states and novel magnetic excitations. Here, we report the structural, thermodynamic, and magnetic properties of a novel magnetic material Li2Co3Se4O12based on x-ray and neutron diffraction, specific heat, magnetization, and x-ray photoelectron spectroscopy measurements. X-ray and neutron diffraction refinements reveal two Co sites Co (1) and Co (2) even though both are in the octahedral environment. While they are not connected along the b and c directions, these octahedra are edge-shared forming the Co (2) – Co (1) – Co (2) trimer chain along the adirection. The magnetic susceptibility exhibits the Curie-Weiss (CW) temperature dependence at high temperatures (above ∼50 K) with the negative CW temperature, a dip centered at T⁎ ∼ 8.0 K, and an antiferromagnetic transition at TN = 3.3 K. The specific heat confirms that there is a phase transition at TN and a hump at T⁎. The long-range magnetic transition at TN implies that, in addition to the intra-chain interaction, there is strong inter-chain interaction, which is likely due to polarized SeO3 bridging between chains. Single crystal neutron diffraction refinement reveals a complex magnetic structure with the angle between Co (1) and Co (2) moments ∼105°. Within the Co (2) – Co (1) – Co (2) trimer, two Co (2) moments are parallelly aligned. Surprisingly, the Co (1) moment (1.92μB) is only half of the Co (2) moment (3.96μB). There is likely the spin-state change for Co (1) from the high-spin state at T > T⁎ to the low-spin state at T < T⁎, causing a dip in the magnetic susceptibility and a hump in the specific heat. When the magnetic field is applied, multiple metamagnetic transitions are found in all directions, implying field-driven magnetic excitations. Our results demonstrate rich magnetic properties of Li2Co3Se4O12 that are sensitive to the external stimuli such as the magnetic field.

Digital Object Identifier (DOI)

https://doi.org/10.1016/j.jmmm.2026.173840

Rights

© 2026 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (C). (http://creativecommons.org/licenses/by/4.0/).

APA Citation

Xing, J., Ye, F., Duong, D., Mu, S., Pan, M. T., & Jin, R. (2026). Complex spin structure in co-trimer-chain Li2Co3Se4O12. Journal of Magnetism and Magnetic Materials, 641, 173840. https://doi.org/10.1016/j.jmmm.2026.173840

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