Journal ArticleDOI
Ferromagnetic Resonance in Thin Films. I. Theory of Normal-Mode Frequencies
TLDR
In this article, a theory for the frequencies of the general ferromagnetic normal modes of a sample of arbitrary shape and size with both exchange and demagnetization energies included.Abstract:
A theory is developed for the frequencies of the general ferromagnetic normal modes of a sample of arbitrary shape and size with both exchange and demagnetization energies included. The frequencies of the modes of rectangular and circular films are calculated by casting the linearized equation of motion of the magnetization into the form of an eigenvalue equation, which is solved by a variational method. The results explain the experiments of Dillon, Besser, Sparks et al., Freedman and Brundle, and Voltmer in detail qualitatively and typically to within \ensuremath{\sim}5-10% quantitatively for the mode spacings, with possible exceptions for the first few low-order modes in some samples, for which several contributions to the line spacings are difficult to estimate accurately. Pinning the surface spins has little effect on the frequencies and intensities of magnetostatic modes (with negligible exchange energy). The theory has implications concerning the main-resonance position in finite films, and together with experiments, further verifies Portis's modespacing theory. A simple physical explanation of the results is given, and the relation of the results for for finite films to those for infinite films is given.read more
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Journal ArticleDOI
Spin wave hybridization via direct mapping of spin wave evolution in ferromagnetic microstructures
Lihui Bai,Lihui Bai,Y. S. Gui,Zhanghai Chen,S. C. Shen,Junsaku Nitta,Can-Ming Hu,L. E. Hayward,M. P. Wismayer,B. W. Southern +9 more
TL;DR: In this article, the authors used a microwave photovoltage technique to map the spin wave evolution between surface, edge, and central modes by tuning the direction of the applied magnetic field.
Journal ArticleDOI
Spin waves in multilayers: geometric effects of antiferromagnetic coupling
TL;DR: Ferromagnetic and antiferromagnetic couplings through the nonmagnetic multilayers in magnetic-non-magnetic multi-layer act as effective local couplings for spin wave resonance in saturating applied fields as discussed by the authors.
Journal ArticleDOI
Magnetostatic modes in finite ferromagnetic circular disks in perpendicular resonance
TL;DR: In this paper, an improved theoretical description of the measured spectrum of magnetostatic modes in finite ferromagnetic circular disks is given, and the mode parameters: resonance fields, mode shifts, and mode intensities are investigated in dependence on the detailed shape of the mode patterns.
Journal ArticleDOI
Radiation damping in FMR measurements in a nonresonant rectangular waveguide
TL;DR: In this paper, the radiation induced line broadening in FMR experiments in a rectangular waveguide terminated to both sides is calculated in dependence on the sample position, which is compared to experimental investigations made at X-band on three single crystal YIG-spheres with various diameters, in order to determine experimentally whether the uniform precession mode is excited in a sample or not or which magnetostatic mode may be excited.
Journal ArticleDOI
Ripple effects in the ferromagnetic resonance spectra of single crystal nickel films
TL;DR: Some features of the ferromagnetic resonance spectra of single crystal nickel films are interpreted in terms of coupling to spin-wave modes via magnetisation ripple effects as discussed by the authors, which can be seen as a kind of spin-warping.