Anomalous resistivity upturn in the van der Waals ferromagnet Fe${}_5$GeTe${}_2$

Abstract

Fe${}_5$GeTe${}_2$ (n = 3, 4, 5) have recently attracted increasing attention due to their two-dimensional van der Waals characteristic and high temperature ferromagnetism, which make promises for spintronic devices. The Fe(1) split site is one important structural characteristic of Fe${}_5$GeTe${}_2$ which makes it very different from other Fe${}_5$GeTe${}_2$ (n = 3, 4) systems. The local atomic disorder and short-range order can be induced by the split site. In this work, the high-quality van der Waals ferromagnet Fe${}_5$GeTe${}_2$ were grown to study the low-temperature transport properties. We found a resistivity upturn below 10 K. The temperature and magnetic field dependence of the resistivity are in good agreement with a combination of the theory of disorder-enhanced three-dimensional electron-electron and single-channel Kondo effect. The Kondo effect exists only at low magnetic field B < 3 T, while electron-electron dominates the appearance for the low-temperature resistivity upturn. We believe that the enhanced three-dimensional electron-electron interaction in this system is induced by the local atomic structural disorder due to the split site of Fe(1). Our results indicate that the split site of Fe plays an important role for the exceptional transport properties.

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• Tuning Magnetic Order in the van der Waals Metal Fe5GeTe2 by Cobalt Substitution
• Gate-controlled magnetic phase transition in a van der Waals magnet Fe${}_5$GeTe${}_2$
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• Magnetism and Spin Dynamics in Room-Temperature van der Waals Magnet Fe${}_5$GeTe${}_2$
• Anomalous Hall Effect in Layered Ferrimagnet MnSb2Te4

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• Observation of Magnetic-Anisotropy Crossover and High-Temperature Skyrmions in the Dirac Magnet Fe3Ge with a Distorted Kagome Lattice