In-Plane Ferromagnetism and Critical Dynamics in Alkali-Deficient K$_{1-x}$CrTe$_2$ (with $x \approx$ 0.3) Single Crystals

Catherine Witteveen; Felix Eder; Sara A. López-Paz; Vladimir Pomjakushin; Jonas A. Krieger; Zurab Guguchia; Harald O. Jeschke; Martin Månsson; Fabian O. von Rohr

arXiv · 2605.20972

In-Plane Ferromagnetism and Critical Dynamics in Alkali-Deficient K$_{1-x}$CrTe$_2$ (with $x \approx$ 0.3) Single Crystals

Catherine Witteveen·Felix Eder·Sara A. López-Paz·Vladimir Pomjakushin·Jonas A. Krieger·Zurab Guguchia·Harald O. Jeschke·Martin Månsson·Fabian O. von Rohr

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Abstract

Layered chromium tellurides are model systems for studying low-dimensional magnetism in van der Waals materials. We report the synthesis and characterization of K$_{1-x}$CrTe$_2$ single crystals ($x \approx 0.3$), which crystallize in the $Cm$ space group with trigonal prismatic K$^+$ coordination, unlike the octahedral environments of more stoichiometric ACrX$_2$ compounds. Magnetization measurements show a sharp ferromagnetic transition at $T_{\rm C}=117$ K and in-plane magnetic anisotropy, supported by density functional theory. Neutron diffraction reveals ferromagnetic alignment of Cr spins within and between layers. This contrasts with the out-of-plane A-type antiferromagnetism in LiCrTe$_2$ and NaCrTe$_2$, but resembles CrTe$_2$. These differences likely arise from changes in interlayer spacing, Cr oxidation state, or stacking. AC susceptibility and $μ$SR indicate short-range order above $T_{\rm C}$ and dynamic behavior below. Overall, K$_{1-x}$CrTe$_2$ provides a tunable platform for studying spin orientation and dimensionality in two-dimensional magnets.

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Catherine Witteveen, Felix Eder, Sara A. López-Paz, Vladimir Pomjakushin, Jonas A. Krieger, Zurab Guguchia, Harald O. Jeschke, Martin Månsson, Fabian O. von Rohr. 2026-05-20. In-Plane Ferromagnetism and Critical Dynamics in Alkali-Deficient K$_{1-x}$CrTe$_2$ (with $x \approx$ 0.3) Single Crystals. https://arxiv.org/abs/2605.20972

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