Goldstone modes and electromagnon fluctuations in the conical cycloid state of a multiferroic
Goldstone modes and electromagnon fluctuations in the conical cycloid state of a multiferroic
Using a phenomenological Ginzburg-Landau theory for the magnetic conical cycloid state of a multiferroic, which has been recently reported in the cubic spinel ${\text{CoCr}}_{2}{\text{O}}_{4}$, we discuss its low-energy fluctuation spectrum. We identify the Goldstone modes of the conical cycloidal order and deduce their dispersion relations whose signature anisotropy in momentum …