Scaling, rotation, and channeling behavior of helical and skyrmion spin textures in thin films of Te-doped Cu ₂ OSeO ₃

Abstract

Topologically nontrivial spin textures such as vortices, skyrmions, and monopoles are promising candidates as information carriers for future quantum information science. Their controlled manipulation including creation and annihilation remains an important challenge toward practical applications and further exploration of their emergent phenomena. Here, we report controlled evolution of the helical and skyrmion phases in thin films of multiferroic Te-doped Cu 2 OSeO 3 as a function of material thickness, dopant, temperature, and magnetic field using in situ Lorentz phase microscopy. We report two previously unknown phenomena in chiral spin textures in multiferroic Cu 2 OSeO 3 : anisotropic scaling and channeling with a fixed-Q state. The skyrmion channeling effectively suppresses the recently reported second skyrmion phase formation at low temperature. Our study provides a viable way toward controlled manipulation of skyrmion lattices, envisaging chirality-controlled skyrmion flow circuits and enabling precise measurement of emergent electromagnetic induction and topological Hall effects in skyrmion lattices.

Anomalous helimagnetic domain shrinkage due to the weakening of Dzyaloshinskii-Moriya interaction in CrAs

“…For example, insitu Lorentz microscopy of Fe 0.5 Co 0.5 Si film showed that magnetic field can effectively deform, rotate and enlarge the helimagnetic domains by applying H along different directions [10]. Similar observation was recently reported in Te-doped Cu 2 OSeO 3 [11]. Here, in the helimagnet CrAs, we observe an anomalous shrinkage of helimagnetic domains with decreasing temperature and find the decrease of DMI in CrAs on cooling as its main driving force.…”

In‐Plane Magnetic Field‐Driven Creation and Annihilation of Magnetic Skyrmion Strings in Nanostructures

“…This multi-Q helical state might be a result of significant contribution of anisotropic demagnetization (stray) field at the low temperatures present in the NPL, which easily transforms to a stable single-Q helical state by increasing H || by ≈100 Oe above zero field (Figure S8e-h, Supporting Information). [42,43] In principle, the transformation of topologically protected SkS to the helical phase is facilitated by the dynamics of Bloch points in the material. In earlier studies, [15,44,45] the transformation of SkS to the helical phase proceeds with the merging of SkS to the formation of Bloch points that travel across the material.…”

Field-induced reorientation of helimagnetic order in Cu2OSeO3 probed by magnetic force microscopy

“…Indeed, additional magnetic phases stabilized by magnetocrystalline anisotropies -the (metastable) canted conical state as well as the low temperature skyrmion lattice phase -were found in Cu 2 OSeO 3 at low temperatures but for H only aligned along crystallographic 100 directions [18][19][20]. Recently, real space observations addressing these states have been reported for a thin Cu 2 OSeO 3 lamella and field along a 100 direction [21].…”