Butterfly-shaped magnetoresistance in van der Waals ferromagnet Fe5GeTe2

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- A nd 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.