Direct Observation of Cycloidal Spin Modulation and Field-induced Transition in Neel-type Skyrmion-hosting VOSe2O5

We investigate the spin rotational structure of magnetic skyrmions in a tetragonal polar magnet VOSe2O5 via polarized small-angle neutron scattering (SANS). Spin polarization analysis of the scattered neutrons provides consistent evidence for the cycloidal spin modulation in all the incommensurate phases at zero and non-zero magnetic field along the c axis, including the triangular skyrmion-lattice phase. In the vicinity of the skyrmion phase, we performed extensive SANS measurements to unravel a field-induced incommensurate phase (IC-2 state). We discuss the possibility of anisotropic double-q state as an alternative spin structure to provisional square skyrmion-lattice state.

Automated summary

The study investigates the spin rotational structure of magnetic skyrmions in tetragonal polar magnet VOSe2O5 using polarized small-angle neutron scattering (SANS). It reveals consistent evidence of cycloidal spin modulation in all incommensurate phases, including the triangular skyrmion-lattice phase, along the c axis. Additionally, a field-induced incommensurate phase (IC-2 state) was identified near the skyrmion phase, suggesting the possibility of an anisotropic double-q state as an alternative spin structure to the provisional square skyrmion-lattice state.