Control of domain structure and magnetization reversal in thick Co/Pt multilayers

We present a study of the magnetic properties of [Co(3.0 nm)/Pt(0.6nm)]N multilayers as a function of Co/Pt bilayer repetitions N. Magnetometry investigation reveals that samples with N 15 exhibit two characteristic magnetization reversal mechanisms, giving rise to two different morphologies of the remanent domain pattern. For applied magnetic field angles near the in-plane field orientation, the magnetization reversal proceeds via a spontaneous instability of the uniform magnetic state resulting in perpendicular stripe domains. Conversely, for field angles close to the out-of-plane orientation, the reversal occurs via domain nucleation and propagation leading to a mazelike domain pattern at remanence. Our measurements further enable the characterization of the N-dependent energy balance between the magnetic anisotropy and magnetostatic energy contributions, revealing a gradual disappearance of the domain nucleation process during magnetization reversal for N < 14. This leads to the exclusive occurrence of an instability reversal mechanism for all field orientations as well as alignedlike stripe domains at remanence. Furthermore, a detailed study of the influence of the magnetic history allows the determination of a range of material properties and magnetic field strengths, where a lattice of bubble domains with remarkably high density is stabilized. These modulations of the ferromagnetic order parameter are found to strongly depend on N, in terms of center-to-center bubble distance as well as of bubble diameter. Moreover, such Co/Pt multilayers could be utilized to engineer field reconfigurable bubble domain lattices, which resemble magnonic crystals.

Keywords

irreversible evolution, stripe domains, x-ray, anisotropy, films, hysteresis, transition, skyrmions

Citation

PHYSICAL REVIEW B. 2019, vol. 99, issue 2, p. 024431-1-024431-16.
https://journals.aps.org/prb/abstract/10.1103/PhysRevB.99.024431

Document type

Peer-reviewed

Document version

submittedVersion

Language of document

en

Document licence

(C) American Physical Society