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Large topological Hall effect in a short-period helimagnet MnGe
1Department of Applied Physics and Quantum Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan.
Physical Review Letters
|May 17, 2011
Summary
Researchers observed a topological Hall effect in MnGe, a chiral magnet. This effect, driven by spin texture, remains consistent below 70 K, indicating a stable fictitious magnetic field.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Magnetism
Background:
- Chiral magnets exhibit unique magnetic properties due to their crystal structure.
- The topological Hall effect (THE) is a phenomenon related to non-collinear spin textures.
- Understanding THE in materials like MnGe is crucial for spintronics.
Purpose of the Study:
- To investigate the unconventional Hall effect in the chiral-lattice helimagnet MnGe.
- To characterize the temperature dependence of the topological Hall resistivity.
- To correlate the observed Hall effect with the material's spin structure.
Main Methods:
- Experimental observation of the Hall effect during magnetization.
- Neutron diffraction studies to determine the spin structure.
- Analysis of topological Hall resistivity and its relation to scalar spin chirality.
Main Results:
- An unconventional, likely topological, Hall effect was observed in MnGe over a wide temperature range.
- The topological Hall resistivity showed near temperature-independence below 70 K.
- A short-period (3-6 nm) noncoplanar spin structure was identified as responsible for the large topological Hall response.
Conclusions:
- The observed Hall effect in MnGe is attributed to a real-space fictitious magnetic field generated by scalar spin chirality.
- MnGe exhibits a robust topological Hall response due to its stabilized noncoplanar spin structure.
- This study highlights MnGe as a promising material for exploring topological phenomena in chiral magnets.
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