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Recent reports of a large anomalous Hall effect (AHE) in ferromagnetic Weyl semimetals (FM WSMs) have led to a resurgence of interest in this enigmatic phenomenon. However, due to a lack of tunable materials, the interplay between the intrinsic mechanism caused by Berry curvature and extrinsic mechanisms due to scattering remains unclear in FM WSMs. In this contribution, we present a thorough investigation of both the extrinsic and intrinsic AHEs in a new family of FM WSMs, PrAlGe1−xSix, where x can be tuned continuously. Based on the first-principles calculations, we show that the two end members, PrAlGe and PrAlSi, have different Fermi surfaces, but similar Weyl node structures. Experimentally, we observe moderate changes in the anomalous Hall coefficient (RS), but significant changes in the ordinary Hall coefficient (R0) in PrAlGe1−xSix as a function of x. By comparing the magnitude of R0 and RS, we identify two regimes: |R0| < |RS| for x ≤ 0.5 and |R0| > |RS| for x > 0.5. Through a detailed scaling analysis, we uncover a universal anomalous Hall conductivity (AHC) from intrinsic contribution when x ≤ 0.5. Such a universal AHC is absent for x > 0.5. Our study, thus, reveals the significance of extrinsic mechanisms in FM WSMs and reports the first observation of the transition from the intrinsic to extrinsic AHE in PrAlGe1−xSix.

We have investigated magnetotransport properties and the topological electronic structure of the half-Heusler compound TbPtBi. Our experiments reveal an exceptionally large anomalous Hall effect (AHE) in the canted antiferromagnetic state of TbPtBi with the anomalous Hall angle (AHA) reaching ~0.68-0.76, which is a few times larger than the previously reported record in GdPtBi. First-principles electronic structure and the associated anomalous Hall conductivity were computed in order to interpret the experimental results. Our analysis shows that the AHE in TbPtBi does not originate from the Weyl points but that it is driven by the large net Berry curvature produced by the anticrossing of spin-split bands near the Fermi level in TbPtBi.

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