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 cm²V⁻¹s⁻¹ at 2 K, which are one of the highest for ferromagnetic materials. These phenomena are due to the spin-polarised Bi 6p 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.

在几种非磁性拓扑外尔半金属中观察到大的非饱和磁阻，这些半金属在费米能级上具有高载流子迁移率。然而，由于费米速度较低的重d带中的局域电子，铁磁系统很少表现出大的磁阻。在这里，我们报告了铁磁 MnBi 具有大的线性非饱和磁阻和高迁移率。与传统铁磁体不同，MnBi 在 70 T 的脉冲场下表现出 5000% 的大线性非饱和磁阻。电子和空穴的迁移率在 2 K 时均为 5000 cm ² V ^-1 s ^-1 ，这是铁磁材料中最高。这些现象是由于自旋极化的Bi 6 p能带在有效质量较小的情况下急剧色散所致。我们的研究提供了一种在高居里温度的铁磁系统中实现高迁移率的方法，这对于拓扑自旋电子学是有利的。