We have performed precise Hall measurements for the ferrotoroidic candidate material UNi4B. Below Neel temperature TN ~ 20 K (corresponding to the ferrotoroidic transition temperature), a Hall voltage becomes finite even at zero field and changes proportional to the square of current density; by contrast, it is almost zero above TN. Moreover, we have found that a current-induced magnetization estimated from our Hall effect measurements is qualitatively consistent with the previous directly measured value. These results provide strong evidence for a magnetoelectric phenomenon uniquely in ferrotoroidic metals -- a zero-field nonlinear Hall effect resulting from the current-induced magnetization connecting the ferrotoroidal moments.
@article{arxiv.2205.05555,
title = {Zero-field current-induced Hall effect in ferrotoroidic metal},
author = {K. Ota and M. Shimozawa and T. Muroya and T. Miyamoto and S. Hosoi and A. Nakamura and Y. Homma and F. Honda and D. Aoki and K. Izawa},
journal= {arXiv preprint arXiv:2205.05555},
year = {2022}
}