Negative differential thermal resistance in coupled rotor lattices

Contributions of homogeneous and Goldstone modes of the spin precession were distinguished in FMR spectra of Cr_1/3NbS₂ chiral helimagnet. The resonance field of homogeneous mode is determined by uniaxial magnetic anisotropy. The resonance field of Goldstone mode is determined by six-fold anisotropy in basal plane. For the first time, it has been shown experimentally that effective excitation of Goldstone mode is realized only when microwave magnetic field vector h is perpendicular to wave vector of magnetic structure Q.