Magnon contributions to dielectric constant in spiral magnets

Magnetic frustration often results in interesting magnetic and dielectric properties. Spiral spin structures are common in magnetic perovskites due to competing exchange interactions and may give rise to ferroelectric polarization via inverse Dzyaloshinskii-Moriya mechanism. Here we model chiral domain walls in the spiral magnetic order and characterize the excitation spectrum using a model Hamiltonian describing spins interacting with polar ionic displacements. We explore the contributions of domain wall localized excitations to the low-frequency dielectric constant in spiral multiferroics (i.e. TbMnO₃, MnWO₄).