  The crystallographic, magnetic, and transport properties of the van der Waals
bonded, layered compound CrTe3 have been investigated on single crystal and
polycrystalline materials. The crystal structure contains layers made up of
lozenge shaped Cr_4 tetramers. Electrical resistivity measurements show the
crystals to be semiconducting, with a temperature dependence consistent with a
band gap of 0.3eV. The magnetic susceptibility exhibits a broad maximum near
300K characteristic of low dimensional magnetic systems. Weak anomalies are
observed in the susceptibility and heat capacity near 55K, and single crystal
neutron diffraction reveals the onset of long range antiferromagnetic order at
this temperature. Strongly dispersive spin-waves are observed in the ordered
state. Significant magneto-elastic coupling is indicated by the anomalous
temperature dependence of the lattice parameters and is apparent in structural
optimization in van der Waals density functional theory calculations for
different magnetic configurations. The cleavability of the compound is apparent
from its handling and is confirmed by first principles calculations, which
predict a cleavage energy 0.5J/m^2, similar to graphite. Based on these
results, CrTe3 is identified as a promising compound for studies of low
dimensional magnetism in bulk crystals as well as magnetic order in monolayer
materials and van der Waals heterostructures.
