Second-Harmonic Response in Magnetic Nodal-Line Semimetal Fe₃GeTe₂

We experimentally investigate second-harmonic transverse voltage response to ac electrical current for a magnetic nodal-line semimetal Fe 3 GeTe 2 (FGT). For zero field, the observed behaves as square of longitudinal current, it should be expected nonlinear Hall effect. The field behavior is found sophisticated: while first-harmonic shows known anomalous hysteresis in FGT, characterized by pronounced high-field and flat ( B -independent) region with curves touching at low fields. strongly depends on sweep rate, so reflects some slow relaxation process. lowest rates, also accomplished multiple crossing points. Similar shape skyrmion spin textures optics. Since skyrmions have been demonstrated FGT direct visualization techniques, we can connect deformation lattice. Thus, regarded tool detect transport experiments.