  The spin-1/2 kagome antiferromagnets are key prototype materials for studying
frustrated magnetism. Three isostructural kagome antiferromagnets
LnCu$_3$(OH)$_6$Cl$_3$ (Ln = Gd, Tb, Dy) have been successfully synthesized by
the hydrothermal method. LnCu$_3$(OH)$_6$Cl$_3$ adopts space group
$P\overline{3}m1$ and features the layered Cu-kagome lattice with lanthanide
Ln$^{3+}$ cations sitting at the center of the hexagons. Although heavy
lanthanides (Ln = Gd, Tb, Dy) in LnCu$_3$(OH)$_6$Cl$_3$ provide a large
effective magnetic moment and ferromagnetic-like spin correlations compared to
light-lanthanides (Nd, Sm, Eu) analogues, Cu-kagome holds an
antiferromagnetically ordered state at around 17 K like YCu$_3$(OH)$_6$Cl$_3$.
