Normal mode mixing and ferromagnetic resonance linewidth

Author

Kunz, Andrew ; McMichael, R.D.

Author_Institution

Nat. Inst. of Stand. & Technol., Gaithersburg, MD, USA

Volume

38

Issue

5

fYear

2002

fDate

9/1/2002 12:00:00 AM

Firstpage

2400

Lastpage

2402

Abstract

The normal modes of an inhomogeneous thin film are obtained by diagonalization of the perturbed Hamiltonian. The resulting modes are mixtures of the spin-wave modes and the uniform mode. We find that the ferromagnetic resonance intensity spectrum of the diagonalized system has a Lorentzian profile, and that the results correspond to the two-magnon model for weak perturbations. For stronger perturbations, the density of states is smoothed, and the spectrum becomes asymmetric due to the low-frequency cutoff of the spin-wave manifold. The technique is expected to be valid for perturbation amplitudes that are large enough to invalidate the assumptions of the two-magnon model.

Keywords

eigenvalues and eigenfunctions; ferromagnetic resonance; magnetic thin films; magnons; spectral line breadth; spin Hamiltonians; Lorentzian profile; eigenstates; ferromagnetic resonance linewidth; inhomogeneous thin film; intermediate coupling regime; low-frequency cutoff; normal mode mixing; perturbed Hamiltonian diagonalization; smoothed density of states; spin-wave manifold; spin-wave modes; symmetric distribution; two-magnon model; uniform mode; weak perturbations; Couplings; Magnetic anisotropy; Magnetic films; Magnetic materials; Magnetic resonance; Magnetostatic waves; NIST; Perpendicular magnetic anisotropy; Scattering; Transistors;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2002.803595

Filename

1042201