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arXiv · 2511.12338

Stoichiometry and Phase Control in K$_{1-x}$CrSe$_2$ via Self-Flux Synthesis

Felix Eder·Catherine Witteveen·Enrico Giannini·Fabian O. von Rohr
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Abstract

Layered delafossite-type magnetic materials, such as KCrSe$_2$, are promising platforms for studying magnetic systems and potential frustration on triangular lattices. Synthesis, structure-type control, and off-stoichiometries remain major challenges in the investigation of these delafossite-type magnets. Starting from the same self-flux composition (K:Cr:Se = 8:1:8), we isolated three distinct K$_{1-x}$CrSe$_2$ phases with $x$ = 0, 0.13--0.17, and 0.32--0.35, each adopting a different structure type depending on the quenching temperature applied. The phase evolution indicates a sequence of transformations during synthesis between compounds with varying degrees of potassium deficiency. Building on these insights into phase stability and crystal growth, we successfully grew single crystals of full-stoichiometric KCrSe$_2$ -- enabling direction-dependent magnetization measurements. These measurements reveal a pronounced field dependence of the N\'{e}el temperature at low external fields, as well as a weak metamagnetic transition. Our findings demonstrate that even a simple parameter -- such as quenching temperature -- can be used to control stoichiometry, direct phase formation, and ultimately tune the magnetic properties of delafossite-type materials.

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Felix Eder, Catherine Witteveen, Enrico Giannini, Fabian O. von Rohr. 2025-11-15. Stoichiometry and Phase Control in K$_{1-x}$CrSe$_2$ via Self-Flux Synthesis. https://doi.org/10.1021/acs.chemmater.5c02075

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