Spin waves in magnetic double layers with strong antiferromagnetic interlayer exchange coupling: Theory and experiment

Abstract

We present a simple approach based on continuum theory to calculate spin-wave frequencies in thin magnetic multilayers taking into account both the nonuniform static and dynamic magnetizations, which are present in systems with strong interlayer exchange coupling. The calculation includes in-plane static magnetization, the canted and twisted state, bilinear and biquadratic interlayer exchange coupling, and the dynamic dipolar coupling. Therefore, we are able to compute accurate spin-wave frequencies in strongly antiferromagnetic coupled trilayers over a full hysteresis loop. We consider the field dependence of the spin-wave frequencies of an epitaxial Fe͑001͒/Si-wedge/Fe sample with strong antiferromagnetic coupling measured by Brillouin light scattering and find excellent agreement with the model calculation. The fits of the experimental curves verify the existence of the twisted state and allow determining the coupling constants with high precision.

Microwave spectroscopy with vector network analyzer for interlayer exchange-coupled symmetrical and asymmetrical NiFe/Ru/NiFe

“…The frequency offset of the optic mode in the simulation is possibly caused by the presence of a significant twisting of the magnetization along the film normal in the real sample. This additional effect can be treated by a multilayer simulation as shown by Buchmeier et al [14].…”

Frequency- and time-domain investigation of the dynamic properties of interlayer-exchange-coupledNi81Fe19∕Ru∕Ni81Belmeguenai1, Martin2, Woltersdorf3 et al. 2007Phys. Rev. B893482View full textAdd to dashboardCite

“…The frequency offset of the optic mode in the simulation is caused by the presence of a significant twisting of the magnetization along the film normal in the real sample. This additional effect can be treated by a multilayer simulation as shown by Buchmeier et al 17 The effect of the biquadratic coupling on the mode frequency has been studied theoretically by Layadi. 10 For antiferromagnetic coupling, two situations can arise.…”

Intensity of Brillouin light scattering from spin waves in magnetic multilayers with noncollinear spin configurations: Theory and experiment

“…25 The calculation of the magnetic ground state and the spin wave frequencies in the extended UTFA is described in detail in Ref. 25.…”

“…However, in our previous work (Ref. 25) we have shown that the UTFA approach can be easily extended in order to accurately describe the modes in thicker films. We thereby included also the exchange modes and the twisted ground state found in exchange springs and also in the case of very strong interlayer exchange coupling.…”

“…In fact, the cross-section calculation using this method only requires a standard treatment of the light propagation in the multilayer apart from the formulae already presented in Ref. 25 . As we will show below, the optics involved is closely related to the magneto-optic Kerr effect (MOKE).…”