Galvanomagnetic Effects in MnBi Films

Transverse Hall effect, planar Hall effect, transverse magnetoresistance effect, and also resistivity were measured on polycrystalline $\mathrm{MnBi}$ thin films which have the uniaxial magnetic anisotropy normal to their film planes(i.e. perpendicular anisotropy). It was found that these $\mathrm{MnBi}$ films exhibit a remarkable extraordinary Hall effect at room temperature and that the hysteresis loop of the extraordinary Hall effect (V_H‐H loop) agrees well with the magnetization curve obtained by the Faraday effect. The Hall resistivity ${\rho }_{\mathrm{H}}\mathrm{(=\hspace{0.17em}}{\mathrm{V}}_{\mathrm{H}}\mathrm{d}/\mathrm{I})$ of the film decreases and the V_H‐H loop change in shape from rectangular to linear as the temperature decreases. Our experimental data on the transverse Hall effect in $\mathrm{MnBi}$ films are considerably different from those reported earlier.