Position-dependent stability and lifetime of the skyrmion state in nickel-substituted Cu2OSeO3

Crisanti, M.; Birch, M.T.; Wilson, M.N.; Moody, S.H.; Štefančič, A.; Huddart, B.M.; Cabeza, S.; Balakrishnan, G.; Hatton, P.D.; Cubitt, R.

Abstract

We report spatially resolved small-angle neutron-scattering measurements of the conical and skyrmion states of a bulk single crystal of nickel-substituted Cu2OSeO3, with a nominal concentration of Ni of 14%. We observe a significant spatial dependence of the structure of these magnetic states, characterized by increased disorder and misalignment with respect to the applied field as we approach the edge of the sample. Remarkably, the edge skyrmion state is also characterized by an extended stability towards lower temperatures. Surprisingly, in the same region of the sample, the metastable skyrmion state did not show simple decay. Instead, only a fraction of the scattered intensity appeared to decay, and the intensity therefore did not approach zero during our measurements. We suggest that the increased local disorder and the coexistence of conical and skyrmion states, induced by demagnetization effects at the edge of the sample, are responsible for the increased stability of this skyrmion state. We also infer that the unclear metastable behavior of the skyrmion lattice at the edge of the sample is due to the local geometry of the sample, which induces coexistence of different skyrmion states whose lifetimes are superimposed and difficult to separate in the data.

Citation

Crisanti, M., Birch, M., Wilson, M., Moody, S., Štefančič, A., Huddart, B., …Cubitt, R. (2020). Position-dependent stability and lifetime of the skyrmion state in nickel-substituted Cu2OSeO3. Physical Review B, 102(22), Article 224407. https://doi.org/10.1103/physrevb.102.224407

• Journal Article Type: Article
• Acceptance Date: Nov 10, 2020
• Online Publication Date: Dec 4, 2020
• Publication Date: Dec 1, 2020
• Deposit Date: Jan 11, 2021
• Publicly Available Date: Oct 26, 2021
• Journal: Physical Review B
• Print ISSN: 2469-9950
• Electronic ISSN: 2469-9969
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 102
• Issue: 22
• Article Number: 224407
• DOI: https://doi.org/10.1103/physrevb.102.224407