In-plane spin canting and 1/3-magnetization-plateaulike behavior in S=3/2 Cr3+ kagome lattice antiferromagnets Cs2KCr3F12 and Cs2NaCr3F12

Abstract

We have investigated the structural and magnetic properties of $S=3/2\phantom{\rule{4pt}{0ex}}{\mathrm{Cr}}^{3+}$ Heisenberg-like kagome lattice antiferromagnets ${\mathrm{Cs}}_{2}{\mathrm{K}}_{}{\mathrm{Cr}}_{3}{\mathrm{F}}_{12}$ and ${\mathrm{Cs}}_{2}{\mathrm{Na}}_{}{\mathrm{Cr}}_{3}{\mathrm{F}}_{12}$ using single crystals. Each compound has a slightly distorted kagome lattice, although the space groups differ for the two compounds. The magnetic data suggest that each compound exhibits the formation of antiferromagnetic ordering with in-plane-spin canting approximately below 6 K. The in-plane coplanar structures are clearly different from disordered ground states of the isostructural ${\mathrm{Ti}}^{3+}$ compounds and out-of-plane coplanar structures of the ${\mathrm{V}}^{3+}$ compounds, which is mainly caused by the differences in the strength of quantum fluctuation and the strength of magnetic anisotropy for these three spin systems. In contrast, as well as the ${\mathrm{Ti}}^{3+}$ and ${\mathrm{V}}^{3+}$ compounds, the magnetization curves show 1/3-magnetization-plateaulike anomalies.