FERROMAGNETIC-RESONANCE IN MULTILAYER [FE CR](N) STRUCTURES WITH NONCOLLINEAR MAGNETIC-ORDERING/

The excitation spectrum in an [Fe/Cr](n) multilayer structure with non collinear magnetic ordering was studied by the ferromagnetic resonance (FMR) method in the frequency interval 9.5-37 GHz at room temperature . Besides an acoustic branch, several additional modes were observed u nder parallel excitation of resonance. The FMR spectrum was calculated analytically in a biquadratic exchange model, neglecting in-plane ani sotropy, for an infinite number of layers in the structure and numeric ally for a finite number of layers contained in real samples. It was s hown that the observed modes correspond to excitation of standing spin waves with wave vectors perpendicular to the film plane. (C) 1998 Ame rican Institute of Physics. [S0021-3640(98)01609-0].