Roselle Ngaloy, Avdelningen för kvantkomponentfysik

Sammanfattning: 

The discovery of van der Waals (vdW) magnets opened a new paradigm for condensed matter physics and spintronic technologies. However, the operations of active spintronic devices with vdW ferromagnets are limited to cryogenic temperatures, inhibiting their broader practical applications. Here, we demonstrate the robust room-temperature operation of lateral spin-valve devices using the vdW itinerant ferromagnets Fe5GeTe2 (FGT) [1] and (Co0.15Fe0.85)5GeTe2 (CFGT) [2] in heterostructures with graphene. We performed room temperature spin transport measurements in non-local spin valve configuration and observed characteristic spin valve switching for both FGT/graphene and CFGT/graphene devices. The room-temperature spintronic properties of FGT and CFGT are measured at the interface with graphene, characterized by a negative spin polarization. Lateral spin-valve together with spin-precession measurements provide unique insights by probing the vdW magnet/graphene interface spintronic properties via spin-dynamics measurements, revealing canted magnetic moments in FGT and in-plane magnetic anisotropy in CFGT. These findings open opportunities for vdW interface design and applications of vdW-magnet-based spintronic devices at ambient temperatures.

[1] Zhao, B., Ngaloy, R., et al. "Room Temperature Spin‐Valve with van der Waals Ferromagnet Fe5GeTe2/Graphene Heterostructure." Advanced Materials (2023): 2209113. https://doi.org/10.1002/adma.202209113
[2] Ngaloy, R., et al. “Strong in-plane magnetization and spin polarization in (Co0.15Fe0.85)5GeTe2/graphene van der Waals heterostructure spin-valve at room temperature”. Accepted in ACS Nano DOI: https://doi.org/10.1021/acsnano.3c07462