Spectra of the transmission T(v), ellipticity p(v) and Faraday rotation angle adv) have been measured in YFeOs single crystals near AFMR mode (vI;JIO m-1 ) using the quasi-optical submillimetre backward-wave-oscillator spectrometer. A resonance behaviour of the T(v), p(v) and adv) spectra was observed near AFMR. The theoretical calculations and computer simulations made it possible to describe the observed T(v), p(v) and a~( v ) spectra and to determine both diagonal and non-diagonal components

more »

... of the permittivity and permeability of the YFe03 . A n unusual effect of the weak magnetic field (H*250 Oe) along magnetic moment (mlloaxis) on the line-shape and intensity of the resonance lime was revealed and explained by an interference of two normal modes inside the resonance line.