Giant topological Hall effect around room temperature in noncollinear ferromagnet NdMn2Ge2 single crystal
Xianming Zheng, Xuanwei Zhao, Ji Qi, Xiaohua Luo, Shengcan Ma, Changcai Chen, Hai Zeng, Guang Yu, Nao Fang, Sajjad Ur Rehman, Weijun Ren, Bing Li, Zhenchen Zhong
Abstract
We report the observation of the giant topological Hall effect near room temperature in a complex noncollinear ferromagnet NdMn2Ge2 single crystal. Three successive magnetic transitions are observed below 400 K, including a spin reorientation transition at TSR = 215 K. The complex noncollinear magnetic structures give rise to anomalous transport behaviors. When the current flows along the a axis and the magnetic field is applied along the c axis, the anomalous Hall effect is observed, which is found to be dominated by the skew scattering mechanism. Strikingly, a giant topological Hall effect appears in a wide temperature range, which stems from the noncollinear spin configuration with finite scalar spin chirality. The topological Hall resistivity reaches the maximum of −1.35 μΩ cm at 300 K and drops slightly with temperature until below TSR. These results suggest that the NdMn2Ge2 single crystal would be a promising topological material for spintronic applications at room temperature.