Dispersion of natural oscillations of magnetic moments in a permalloy film: Mandel'shtam-Brillouin scattering data

 

V. D. Bessonov, A V. Telegin, V. A. Bessonova, V. S. Teplov, M. A. Milyaev, Yu. P. Sukhorukov

M.N. Mikheev Institute of Metal Physics of the Ural Branch of the Russian Academy of Sciences, S.Kovalevskoy str. 18, Ekateringurg 620108, Russia

 

The paper is received on December 11, 2018

 

Abstract. The field dependence of ferromagnetic resonance and spin-wave resonance for 40 nm thick polycrystalline permalloy film grown on a silicon substrate was studied using the Brillouin light scattering method. The experiment was carried out in the geometry of the inverse and quasi-inverse light scattering at room temperature. An external magnetic field was applied along the film surface in accordance with the Diman-Eshbach geometry. It is shown that the observed ferromagnetic resonance frequencies are in good agreement with theoretical calculations. The coincidence of the spin-wave resonance frequencies for the calculated and experimental data in the tangentially magnetized film occurs when the inhomogeneous exchange constant and the surface anisotropy constant for completely fixed surface spins are taking into account. The difference between the Stokes lines intensity of scattered light for ferromagnetic and spin-wave resonances is explained by the penetration depth of the electromagnetic wave and its interaction with the spin waves in the skin layer. The dispersion of surface and pseudo-surface magnetostatic spin waves was studied in the nanosized permalloy film. Dispersion dependence of the MSW was measured by the film deviation from the normal incidence of light. The obtained experimental results are explained by taking into account the dipole-dipole and exchange interactions. The changes of the intensity of the Stokes peak in the Brillouin light scattering spectra depend of the deflection angle because the surface magnetostatic spin waves has a hyperbolic distribution of the intensity of the dynamic magnetization vector over the sample thickness and the nonlinear dependence of light reflection on the angle of incidence for polarized light. The observed peak in the spectra with zero wave vector was associated with the contribution from Rayleigh light scattering at a normal angle of incidence.

Key words: Brillouin light scattering, magnetostatic spin waves, spin wave resonance, permalloy.

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For citation:

V. D. Bessonov, A V. Telegin, V. A. Bessonova, V. S. Teplov, M. A. Milyaev, Yu. P. Sukhorukov. Dispersion of natural oscillations of magnetic moments in a permalloy film: Mandel'shtam-Brillouin scattering data. Zhurnal Radioelektroniki - Journal of Radio Electronics. 2018. No. 12. Available at http://jre.cplire.ru/jre/dec18/16/text.pdf

DOI  10.30898/1684-1719.2018.12.16