Crystal growth, exfoliation, and magnetic properties of quaternary quasi-two-dimensional <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">CuCrP</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">S</mml:mi><mml:mn>6</mml:mn></mml:msub></mml:math>
S. Selter, Kranthi Kumar Bestha, Pritam Bhattacharyya, Burak Özer, Yuliia Shemerliuk, Maria Roslova, Ekaterina Vinokurova, L. T. Corredor, Louis Veyrat, A. U. B. Wolter, Liviu Hozoi, B. Büchner, Saicharan Aswartham
Abstract
We report optimized crystal growth conditions for the quaternary compound ${\mathrm{CuCrP}}_{2}{\mathrm{S}}_{6}$ by chemical vapor transport. Compositional and structural characterization of the obtained crystals were carried out by means of energy-dispersive x-ray spectroscopy and powder x-ray diffraction. ${\mathrm{CuCrP}}_{2}{\mathrm{S}}_{6}$ is structurally closely related to the ${M}_{2}{\mathrm{P}}_{2}{\mathrm{S}}_{6}$ family ($M$: transition metal), which contains several compounds that are under investigation as 2D magnets. As-grown crystals exhibit a platelike, layered morphology as well as a hexagonal habitus. We present successful exfoliation of such as-grown crystals down to thicknesses of 2.6 nm corresponding to four layers. ${\mathrm{CuCrP}}_{2}{\mathrm{S}}_{6}$ crystallizes in the monoclinic space group $C2/c$. Magnetization measurements reveal an antiferromagnetic ground state with ${T}_{\text{N}}\ensuremath{\approx}30$ K and a positive Curie-Weiss temperature in agreement with dominant ferromagnetic intralayer coupling. Specific heat measurements confirm this magnetic phase transition and the magnetic order is suppressed in an external magnetic field of about 6 T (8 T) applied parallel (perpendicular) to the $ab$ plane. At higher temperatures between 140--200 K, additional broad anomalies associated with structural changes accompanying antiferroelectric ordering are detected in our specific heat studies.