Abstract
Skyrmions with multiple helicity or topology in centrosymmetric crystals are intriguing magnetic-domain objects due to their diverse dynamics under external stimuli. Here we illustrate how the two key gradients of magnetocrystalline anisotropy (MCA) and spin reorientation transition (SRT) affect the skyrmion formation and topology by Cu substitution in the biskyrmion-host MnNiGa alloy. The MCA and SRT are simultaneously tuned in a large scope, while the original high Curie temperature (TC) is retained. Detailed neutron-scattering studies revealed the construction of a noncollinear canted magnetic structure below the SRT temperature (TSR), which effectively correlates the SRT with the evolution of the MCA, as well as the exchange interaction. The Cu substitution raises the TSR to merge with the TC, and meanwhile, reduces the c-axis anisotropy. Lorentz transmission electron microscopy revealed the formation of stacked biskyrmions from above room temperature to lower temperatures in MnNi1-xCuxGa(x=0-0.3) in the presence of proper MCA. Micromagnetic simulations further confirmed the great effect of uniaxial anisotropy on the stabilization of biskyrmions. Our work has helped clarify the evolution of magnetic structures and their correlation to the SRT, providing an account of the effect of MCA and exchange interaction on the biskyrmion formation.
Original language | English (US) |
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Journal | Physical Review B |
Volume | 100 |
Issue number | 5 |
DOIs | |
State | Published - Aug 13 2019 |
Externally published | Yes |
Bibliographical note
KAUST Repository Item: Exported on 2021-03-31Acknowledgements: This work was supported by the National Natural Science Foundation of China (Grant No. 11604148), the National Key R&D Program of China (Grant No. 2017YFA0303202), and the Key Research Program of the Chinese Academy of Sciences, KJZD-SW-M01. Z.X.C. thanks the Australia Research Council for support (DP190100150). We also would like to acknowledge Dr. Junye Yang at the Paul Scherrer Institute,
Switzerland, and Dr. Qiang Zhang at King Abdullah University of Science and Technology (KAUST), Saudi Arabia, for technical support and helpful discussions.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.