Abstract
CrAs is a well-known helimagnet with the double-helix structure originating from the competition between the Dzyaloshinskii-Moriya interaction (DMI) and antiferromagnetic exchange interaction J. By resonant soft-x-ray scattering, we observe the magnetic peak (0 0 qm) that emerges at the helical transition with TS≈267.5K. Intriguingly, the helimagnetic domains significantly shrink on cooling below ∼255K, opposite to the conventional thermal effect. The weakening of DMI on cooling is found to play a critical role here. It causes the helical wave vector to vary, ordered spins to rotate, and extra helimagnetic domain boundaries to form at local defects, thus leading to the anomalous shrinkage of helimagnetic domains. Our results indicate that the size of magnetic helical domains can be controlled by tuning DMI in certain helimagnets.
| Original language | English |
|---|---|
| Article number | 104432 |
| Journal | Physical Review B |
| Volume | 102 |
| Issue number | 10 |
| DOIs | |
| State | Published - Sep 2020 |
| Externally published | Yes |
Funding
The authors are grateful for the helpful discussions with Jiang Xiao, Yi-Zheng Wu, and Yan Chen of Fudan University. This work is supported by the National Natural Science Foundation of China (Grants No. 11888101, No. 11790312, No. 11804137, and No. 11704074), the National Key Research and Development Program of China (Grants No. 2016YFA0300200 and No. 2017YFA0303104), the Science and Technology Commission of Shanghai Municipality (Grant No. 15ZR1402900), and the Natural Science Foundation of Shandong Province (Grant No. ZR2018BA026). Part of the research described in this paper was performed at the Canadian Light Source, a national research facility of University of Saskatchewan, which is supported by the Canada Foundation for Innovation (CFI), the Natural Sciences and Engineering Research Council (NSERC), the National Research Council (NRC), the Canadian Institutes of Health Research (CIHR), the Government of Saskatchewan, and the University of Saskatchewan.