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تسجيل مستخدم جديدSkyrmion Dynamics in Multiferroic Insulator
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Recent discovery of Skyrmion crystal phase in insulating multiferroic compound Cu$_2$OSeO$_3$ calls for new ways and ideas to manipulate the Skyrmions in the absence of spin transfer torque from the conduction electrons. It is shown here that the position-dependent electric field, pointed along the direction of the average induced dipole moment of the Skyrmion, can induce the Hall motion of Skyrmion with its velocity orthogonal to the field gradient. Finite Gilbert damping produces longitudinal motion. We find a rich variety of resonance modes excited by a.c. electric field.
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Cu2OSeO3 is known as a unique example of insulating multiferroic compounds with skyrmion spin texture, which is characterized by the chiral cubic crystal structure at ambient pressure. Recently, it has been reported that this compound shows pressure-
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001>$ was identified. When a magnetic field is applied, a triple-$q$ magnetic structure emerges normal to the field in the A-phase just below the magnetic ordering temperature $T_c$, which suggests the formation of a triangular lattice of skyrmions. Notably, the favorable $q$-direction in the A-phase changes from $q parallel <110>$ to $q parallel <001>$ upon approaching $T_c$. Near the phase boundary between these two states, the external magnetic field induces a 30$^circ$-rotation of the skyrmion lattice. This suggests a delicate balance between the magnetic anisotropy and the spin texture near $T_c$, such that even a small perturbation significantly affects the ordering pattern of the skyrmions.
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