Fig. 4: Direct imaging of the room-temperature ferromagnetic properties of single sheet few-UC CrTe crystals by magnetic force microscopy (MFM) at nanoscale.

a Topography image (left) of an 8 nm thick (~10 UC) CrTe crystal with corresponding in-site MFM phase image (right) by a pre-magnetized AFM tip. b Topography images (left) with corresponding in-site MFM phase images (right) for several stacked 3 nm thick (~tri-UC) few-UC CrTe crystals with pre-magnetized AFM tip. c, d MFM phase angle distribution (d) of selected regions for substrate (red), single tri-UC CrTe (few-UC-1, green) and two stacked tri-UC CrTe (few-UC 2, blue) for in (c) with 300, 100, and 50 nm side width (up to down in MFM phase image in (c)). e MFM phase angle difference in substrate, few-UC-1, and few-UC-2 CrTe crystals with side width from 10 to 300 nm. No external magnetic field is applied on few-UC CrTe during all the MFM tests. Error bars s.e.m.; N = 30.