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arXiv · 1905.03318

Incommensurate magnetism in K$_2$MnS$_{2-x}$Se$_x$ and prospects for tunable frustration in a triangular lattice of pseudo-1D spin chains

Ankita Bhutani·Piush Behera·Rebecca D. McAuliffe·Huibo Cao·Ashfia Huq·Melanie J. Kirkham·Clarina dela Cruz·Toby Woods·Daniel P. Shoemaker
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Abstract

We report the first detailed investigation of K$_2$MnS$_2$ and K$_2$MnSe$_2$ from the K$_2$MnS$_2$ structure type and their magnetic solid solution K$_2$MnS$_{2-x}$Se$_x$ and find that compounds of this structure type consist of strongly-coupled pseudo-one-dimensional antiferromagnetic chains that collectively represent a frustrated two-dimensional triangular antiferromagnet. Bulk samples of K$_2$MnS$_{2-x}$Se$_x$ with $0 \leq x \leq 2$ are characterized using X-ray diffraction, neutron diffraction, magnetization and heat capacity measurements. An incommensurate cycloid magnetic structure with a magnetic propagation vector $k = [0.58~0~1]$ is observed for all samples in K$_2$MnS$_{2-x}$Se$_x$, and the ordering is robust despite a 12\% increase in cell volume. Geometric frustration of chains results in incommensurability along $a$ and a two-step magnetic transition. The varying geometries accessible in compounds of this structure type are presented as promising avenues to tune frustration.

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Ankita Bhutani, Piush Behera, Rebecca D. McAuliffe, Huibo Cao, Ashfia Huq, Melanie J. Kirkham, Clarina dela Cruz, Toby Woods, Daniel P. Shoemaker. 2019-05-08. Incommensurate magnetism in K$_2$MnS$_{2-x}$Se$_x$ and prospects for tunable frustration in a triangular lattice of pseudo-1D spin chains. https://doi.org/10.1103/physrevmaterials.3.064404

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