MAGNETOOPTICAL EFFECTS AT SUBMILLIMETER WAVELENGTHS NEAR AFMR IN YFEO3

Spectra of the transmission T(v), ellipticity p(v) and Faraday rotatio n angle alpha F(v) have been measured in YFeO3 single crystals near AF MR mode (v1 approximate to 10 cm(-1)) using the quasi-optical submilli metre backward-wave-oscillator spectrometer. A resonance behaviour of the T(v), p(v) and alpha F(v) spectra was observed near AFMR. The theo retical calculations and computer simulations made it possible to desc ribe the observed T(v), p(v) and alpha F(v) spectra and to determine b oth diagonal and non-diagonal components of the permittivity and perme ability of the YFeO3. An unusual effect of the weak magnetic field (H approximate to 250 Oe) along magnetic moment (m parallel to c-axis) on the line-shape and intensity of the resonance line was revealed and e xplained by an interference of two normal modes inside the resonance l ine.