Antiferromagnetic resonance in Rb2MnCl4

Abstract
Antiferromagnetic resonance (AFMR) experiments on a single-crystal sample of Rb2MnCl4 have been performed using a spectrometer with wide frequency and magnetic field ranges. All the AFMR modes predicted for a uniaxial antiferromagnet have been observed. We find a significant contribution of the non-linear term in the expression of the AFMR frequency to the temperature dependence of the resonance point in the high-field low-frequency region.