Skyrmion lattice formation and destruction mechanisms probed with TR-SANS
- University of Tennessee, Knoxville, TN (United States)
- National Institute of Standards and Technology, Gaithersburg, MD (United States)
- National Taiwan University, Taipei (Taiwan); National Taipei University of Technology (Taiwan)
- National Institute of Standards and Technology, Gaithersburg, MD (United States); University of Maryland, College Park, MD (United States)
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Magnetic skyrmions are topologically protected, nanoscale whirls of the spin configuration that tend to form hexagonally ordered arrays. As a topologically non-trivial structure, the nucleation and annihilation of the skyrmion, as well as the interaction between skyrmions, varies from conventional magnetic systems. Recent works have suggested that the ordering kinetics in these materials occur over millisecond or longer timescales, which is unusually slow for magnetic dynamics. The current work investigates the skyrmion ordering kinetics, particularly during lattice formation and destruction, using time-resolved small angle neutron scattering (TR-SANS). Evaluating the time-resolved structure and intensity of the neutron diffraction pattern reveals the evolving real-space structure of the skyrmion lattice and the timeframe of the formation. Measurements were performed on three prototypical skyrmion materials: MnSi, (Fe,Co)Si, and Cu2OSeO3. To probe lattice formation and destruction kinetics, the systems were prepared in the stable skyrmion state, and then a square-wave magnetic field modulation was applied. The measurements show that the skyrmions quickly form ordered domains, with a significant distribution in lattice parameters, which then converge to the final structure; the results confirm the slow kinetics, with formation times between 10 ms and 99 ms. Comparisons are made between the measured formation times and the fundamental material properties, suggesting the ordering temperature, saturation magnetization and magnetocrystalline anisotropy may be driving the timeframes. Micromagnetic simulations were also performed and support a scaling of the kinetics with sample volume, a behavior which is caused by the reconciling of misaligned domains.
- Research Organization:
- University of Tennessee, Knoxville, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); National Science Foundation (NSF)
- Grant/Contract Number:
- SC0021344
- OSTI ID:
- 3013097
- Alternate ID(s):
- OSTI ID: 2346233
- Journal Information:
- Nanoscale, Journal Name: Nanoscale Journal Issue: 22 Vol. 16; ISSN 2040-3364; ISSN 2040-3372
- Publisher:
- Royal Society of Chemistry (RSC)Copyright Statement
- Country of Publication:
- United States
- Language:
- English