Large linear non-saturating magnetoresistance and high mobility in ferromagnetic MnBi
Yangkun He, Jacob Gayles, M. Yao, Toni Helm, Tommy Reimann, Vladimir N. Strocov, Walter Schnelle, M. Nicklas, Yan Sun, Gerhard H. Fecher, Claudia Felser
Abstract
Abstract A large non-saturating magnetoresistance has been observed in several nonmagnetic topological Weyl semi-metals with high mobility of charge carriers at the Fermi energy. However, ferromagnetic systems rarely display a large magnetoresistance because of localized electrons in heavy d bands with a low Fermi velocity. Here, we report a large linear non-saturating magnetoresistance and high mobility in ferromagnetic MnBi. MnBi, unlike conventional ferromagnets, exhibits a large linear non-saturating magnetoresistance of 5000% under a pulsed field of 70 T. The electrons and holes’ mobilities are both 5000 cm 2 V −1 s −1 at 2 K, which are one of the highest for ferromagnetic materials. These phenomena are due to the spin-polarised Bi 6 p band’s sharp dispersion with a small effective mass. Our study provides an approach to achieve high mobility in ferromagnetic systems with a high Curie temperature, which is advantageous for topological spintronics.