Figure 5.

Magnetic contrast of Fe₅GeTe₂ monolayers and determination of the transition temperature. (a–c) Temperature dependent XPEEM images of bi- and monolayer Fe₅GeTe₂ flakes. At 60 and 120 K, the middle section of the flake, which is a monolayer (see sketch in (c)), shows clear domain contrast. The size and distribution of the domains is similar to the neighboring bilayer areas. Note that, in contrast to Fe₅GeTe₂, Fe₃GeTe₂ exhibits a single-domain state in the monolayer limit.³⁶ Above 150 K, the contrast in the monolayer area has vanished, indicating a transition temperature between 120 and 150 K. The edge of the monolayer area is indicated by yellow arrows.