  The realization of long-range magnetic ordering in two-dimensional (2D)
systems can potentially revolutionize next-generation information technology.
Here, we report the successful fabrication of crystalline Cr3Te4 monolayers
with room temperature ferromagnetism. Using molecular beam epitaxy, the growth
of 2D Cr3Te4 films with monolayer thickness is demonstrated at low substrate
temperatures (~100C), compatible with Si CMOS technology. X-ray magnetic
circular dichroism measurements reveal a Curie temperature (Tc) of ~344 K for
the Cr3Te4 monolayer with an out-of-plane magnetic easy axis, which decreases
to ~240 K for the thicker film (~ 7 nm) with an in-plane easy axis. The
enhancement of ferromagnetic coupling and the magnetic anisotropy transition is
ascribed to interfacial effects, in particular the orbital overlap at the
monolayer Cr3Te4/graphite interface, supported by density-functional theory
calculations. This work sheds light on the low-temperature scalable growth of
2D nonlayered materials with room temperature ferromagnetism for new magnetic
and spintronic devices.
