Ferromagnetism in freestanding MoS(2) nanosheets

Freestanding MoS(2) nanosheets with different sizes were prepared through a simple exfoliated method by tuning the ultrasonic time in the organic solvent. Magnetic measurement results reveal the clear room-temperature ferromagnetism for all the MoS(2) nanosheets, in contrast to the pristine MoS(2) in its bulk form which shows diamagnetism only. Furthermore, results indicate that the saturation magnetizations of the nanosheets increase as the size decreases. Combining the X-ray photoelectron spectroscopy, transmission electron microscopy, and electron spin resonance results, it is suggested that the observed magnetization is related to the presence of edge spins on the edges of the nanosheets. These MoS(2) nanosheets may find applications in nanodevices and spintronics by controlling the edge structures.