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  • Mathur
    Participant
    September 27, 2022 at 12:53 pm #1065

    DOI : https://doi.org/10.1021/acsnano.2c08155
    This paper present methods to distinguish between the “genuine topological hall effect (THE)” signal with “artificial topological hall effect (THE)” found as transport signature in Hall effect measurements. As our group have seen/taken many Hall transport measurements, this paper will provide a good understanding that how to analyze data properly.

    Abstract
    In transport, the topological Hall effect (THE) presents itself as nonmonotonic features (or humps and dips) in the Hall signal and is widely interpreted as a sign of chiral spin textures, like magnetic skyrmions. However, when the anomalous Hall effect (AHE) is also present, the coexistence of two AHEs could give rise to similar artifacts, making it difficult to distinguish between genuine THE with AHE and two-component AHE. Here, we confirm genuine THE with AHE by means of transport and magneto-optical Kerr effect (MOKE) microscopy, in which magnetic skyrmions are directly observed, and find that genuine THE occurs in the transition region of the AHE. In sharp contrast, the artifact ā€œTHEā€ or two-component AHE occurs well beyond the saturation of the ā€œAHE componentā€ (under the false assumption of THE + AHE). Furthermore, we distinguish artifact ā€œTHEā€ from genuine THE by three methods: (1) minor loops, (2) temperature dependence, and (3) gate dependence. Minor loops of genuine THE with AHE are always within the full loop, while minor loops of the artifact ā€œTHEā€ may reveal a single loop that cannot fit into the ā€œAHE componentā€. In addition, the temperature or gate dependence of the artifact ā€œTHEā€ may also be accompanied by a polarity change of the ā€œAHE componentā€, as the nonmonotonic features vanish, while the temperature dependence of genuine THE with AHE reveals no such change. Our work may help future researchers to exercise caution and use these methods for careful examination in order to ascertain the genuine THE.