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Volume 35, Issue 12, December 2009
- LOW-TEMPERATURE MAGNETISM
35(2009); http://dx.doi.org/10.1063/1.3272560View Description Hide Description
The antiferromagnetic resonance (AFMR) spectra along the principal magnetic axes , , of the compound have been investigated in detail in a wide range of frequencies and magnetic fields (up to ) at . It is shown that this compound is a biaxial magnetic substance. At , there are two gaps in the spin-wave spectrum: and . The AFMR data were used to determine the effective magnetic-anisotropy fields: and . An anomalous interaction of the AFMR branches in has been detected, along with the appearance of coupled spin–spin oscillations of the same symmetry. An additional absorption in the AFMR spectrum is a local mode associated with breakdown of translational order in a low-dimension magnet. It is shown for the first time that the appearance of additional absorption peaks depends on the sample-cooling rate. It is proven that the observed peaks are associated with the internal modes of the domain boundaries.