Robust cycloid crossover driven by anisotropy in the skyrmion host ${\mathrm{GaV}}_4{\mathrm{S}}_8$

Journal Article · Sun Mar 01 00:00:00 EST 2020 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.101.094425· OSTI ID:1606023

Clements, E. M. ^[1]; Das, R. ^[2]; Pokharel, G. ^[3]; Phan, M. H. ^[1]; Christianson, A. D. ^[4]; Mandrus, D. ^[5]; Prestigiacomo, J. C. ^[6]; Osofsky, M. S. ^[6]; Srikanth, H. ^[1]

---

1. Univ. of South Florida, Tampa, FL (United States). Dept. of Physics
2. Phenikaa Univ., Hanoi (Vietnam)
3. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
5. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy and Dept. of Materials Science and Engineering; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
6. Naval Research Lab. (NRL), Washington, DC (United States)

We report on the anomalous magnetization dynamics of the cycloidally modulated spin textures under the influence of uniaxial anisotropy in multiferroic GaV₄S₈. The temperature and field dependence of the linear ac susceptibility [$$χ'_{1ω}$$ (T, H)], AC magnetic loss [$$χ''_{1ω}$$ (T, H)], and nonlinear AC magnetic response [$$M_{3ω}$$ (T, H)] are examined across the magnetic phase diagram in the frequency range f = 10 - 10 000 Hz. According to recent theory, skyrmion vortices under axial crystal symmetry are confined along specific orientations, resulting in enhanced robustness against oblique magnetic fields and altered spin dynamics. We characterize the magnetic response of each spin texture and find that the dynamic rigidity of the Néel skyrmion lattice appears enhanced compared to Bloch-type skyrmions in cubic systems, even in the multidomain state. Anomalous M 3 ω and strong dissipation emerge over the same phase regime where strong variations in the cycloid pitch were observed on lowering temperature in recent small-angle neutron-scattering experiments [White et al., Phys. Rev. B 97, 020401(R) (2018)]. Here, we show that strong anisotropy also drives an extended crossover of the zero-field cycloid texture in GaV₄S₈. The frequency dependence of these dynamic signatures is consistent with that of a robust anharmonic spin texture exhibiting a correlated domain arrangement. The results underpin the essential role of magnetic anisotropy in enhancing the rigidity of topological spin textures for diverse applications.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Grant/Contract Number: AC05-00OR22725; FG02-07ER46438
• OSTI ID: 1606023
• Alternate ID(s): OSTI ID: 1605491
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 9 Vol. 101; ISSN 2469-9950; ISSN PRBMDO
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AC susceptibility measurements
Magnetic phase transitions
Magnetic texture
Magnetization dynamics
Noncentrosymmetric materials
Noncollinear magnets
Skyrmions
Symmetry protected topological states