Magnetic Excitations in the Spin-Spiral State of TbMnO${}_3$ and DyMnO${}_3$

Abstract

We calculate spectra of magnetic excitations in the spin-spiral state of perovskite manganates. The spectra consist of several branches corresponding to different polarizations and different ways of diffraction from the static magnetic order. Goldstone modes and opening of gaps at zero and non-zero energies due to the crystal field and the Dzyaloshinski-Moriya anisotropies are discussed. Comparing results of the calculation with available experimental data we determine values of effective exchange parameters and anisotropies. To simplify the spin-wave calculation and to get a more clear physical insight in the structure of excitations we use the σ-model-like effective field theory to analyze the Heisenberg Hamiltonian and to derive the spectra.

arXiv comment8 pages, 8 figures

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• Ferroelectricity in spiral magnets
• Magnetic inversion symmetry breaking and ferroelectricity in TbMnO3
• Quantum Magnetic Excitations from Stripes in Copper-Oxide Superconductors
• Neutron diffraction study of TbMnO3: Magnetic structure revisited
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Cited by in corpus (5)

• Polarizability of electrically induced magnetic vortex plasma
• Spin-wave dispersion and magnon chirality in multiferroic TbMnO3
• Properties of the spin liquid phase in the vicinity of the Néel - Spin-Spiral Lifshitz transition in frustrated magnets
• Electron spin resonance in spiral antiferromagnet linarite: theory and experiment
• Quantum Lifshitz criticality in a frustrated two-dimensional XY model