Abstract
We have performed magnetoresistance (MR) measurements on van der Waals ferromagnetic devices using quenched- (Q-) and nonquenched- (NQ-) Fe5GeTe2 crystals. A clear butterfly-shaped hysteresis has been observed for thin-film (less than 6 unit-cell layer) Q- and NQ-Fe5GeTe2 devices, but not for thicker film ones. The switching field of the butterfly-shaped MR is consistent with the coercive filed obtained from the Hall measurements. The MR ratio of the butterfly peak reaches about 10% at maximum, which is much larger than that observed with conventional magnetic materials. Such a large MR ratio would be related to magnetic fluctuations due to the complicated magnetic structure in this material.
Highlights
A group of atomic-layered materials has attracted much attentions.1–6 Those can be mechanically exfoliated by means of the Scotch tape method,2 maintaining the high crystallinity
A ferromagnetic transition has been demonstrated in a single layer of ferromagnetic insulator CrI3, ferromagnetic semiconductor Cr2Ge2Te6, and ferromagnetic metals such as V5Se8 and Fe3GeTe2.15–21 atomic-layered ferromagnets have been intensively studied from the viewpoint of applications such as spintronic devices, the Curie temperature Tc of these materials is still lower than room temperature
The reason why a clear butterfly-shaped hysteresis could not be observed in the thicker-film devices is that the perpendicular magnetic anisotropy (PMA) becomes weaker with increasing the number of L and the magnetization gradually flips
Summary
A group of atomic-layered materials has attracted much attentions. Those can be mechanically exfoliated by means of the Scotch tape method, maintaining the high crystallinity. A group of atomic-layered materials has attracted much attentions.. A group of atomic-layered materials has attracted much attentions.1–6 Those can be mechanically exfoliated by means of the Scotch tape method, maintaining the high crystallinity. They are expected to be applied to high-purity thinfilm devices.7–12 Another attractive point is that this technique can be used for any cleavable materials with different physical properties. On the other hand, such an MR was not observed in Fe5GeTe2 devices thicker than 10 unit-cell layers (10L). These experimental results suggest that magnetic fluctuations are enhanced at a temperature where one of the Fe sites is ordered and with decreasing the number of L of Fe5GeTe2
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
