We present a detailed numerical simulation study of the effects caused by the magnetodipolar interaction between ferromagnetic ͑FM͒ layers of a trilayer magnetic nanoelement on its magnetization dynamics. As an example, we use a Co/ Cu/ Ni 80 Fe 20 element with a square lateral shape where the magnetization of FM layers forms a closed Landau-like domain pattern. First, we show that when the thickness of the nonmagnetic ͑NM͒ spacer is in the technology relevant region h ϳ 10 nm, magnetodipolar interaction between 90°Neel domain walls in FM layers qualitatively changes the equilibrium magnetization state of these layers. In the main part of the paper, we compare the magnetization dynamics induced by a sub-nsec field pulse in a single-layer Ni 80 Fe 20 ͑Py͒ element and in the Co/ Cu/ Py trilayer element. Here, we show that ͑i͒ due to the spontaneous symmetry breaking of the Landau state in the FM/NM/FM trilayer, its domains and domain walls oscillate with different frequencies and have different spatial oscillation patterns; ͑ii͒ magnetization oscillations of the trilayer domains are strongly suppressed due to different oscillation frequencies of domains in Co and Py; ͑iii͒ magnetization dynamics qualitatively depends on the relative rotation sense of magnetization states in Co and Py layers and on the magnetocrystalline anisotropy kind of Co crystallites. Finally, we discuss the relation of our findings with experimental observations of magnetization dynamics in magnetic trilayers, performed using the element-specific time-resolved x-ray microscopy
