ملخص: The resonance modes of two coupled ferromagnetic layers are investigated as a function of the relative directions of the in-plane anisotropy easy axes of the layers, measured by the angle [delta][ccirf] It is found that the angle [delta] affects differently the acoustic and the optical mode positions and intensities. These effects are described. In some cases, the changes induced by [delta] on the mode position and intensity are similar to those induced by the bilinear J1 and biquadratic J2 coupling strengths. This may lead to incorrect interpretation of the FMR data and consequently to erroneous values of J1 and J2. For ferromagnetic coupling (J1>0) and for magnetizations which are parallel, the variation of the resonant frequency and mode intensity with [delta] is qualitatively similar to that corresponding to a decrease in the bilinear coupling strength, J1. In this case, if [delta] is omitted, then the J1 value derived from FMR will be underestimated. When the magnetizations are antiparallel (J1J2| value; and even the critical field will be the same. Hence, a slight deviation of the easy axis direction of one layer with respect to the one of the second layer may be interpreted as the existence of a small biquadratic coupling. A relation establishing the equivalence between J2 and [delta] in the small (J2, [delta]) region, is derived.

لغة: إنجليزية