Dissipation processes in the insulating skyrmion compound Cu2OSeO3

We present a detailed study of the phase diagram surrounding the skyrmion lattice (SkL) phase of Cu2OSe2O3 using high-precision magnetic ac susceptibility measurements. An extensive investigation of transition dynamics around the SkL phase using the imaginary component of the susceptibility revealed that at the conical-to-SkL transition a broad dissipation region exists with a complex frequency dependence. The analysis of the observed behavior within the SkL phase indicates a distribution of relaxation times intrinsically related to SkL. At the SkL-to-paramagnet transition a narrow first-order peak is found that exhibits a strong frequency and magnetic field dependence. Surprisingly, very similar dependence has been discovered for the first-order transition below the SkL phase, i.e. where the system enters the helical and conical state(s), indicating similar processes across the order-disorder transition.Comment: Accepted for publication in PR

Electric-field control of the skyrmion lattice in Cu2OSeO3

Small-angle neutron scattering has been employed to study the influence of applied electric (E-) fields on the skyrmion lattice in the chiral lattice magnetoelectric Cu2OSeO3. In an experimental geometry with the E-field parallel to the [111] axis, and the magnetic field parallel to the [1-10] axis, we demonstrate that the effect of applying an E-field is to controllably rotate the skyrmion lattice around the magnetic field axis. Our results are an important first demonstration for a microscopic coupling between applied E-fields and the skyrmions in an insulator, and show that the general emergent properties of skyrmions may be tailored according to the properties of the host system.Comment: 12 pages, 4 figures, published version (including final proof corrections). Article is free to download at http://iopscience.iop.org/0953-8984/24/43/432201