Ferromagnetic resonance line broadening and shift effect in nanocrystalline thin magnetic films: Relation with crystalline and magnetic structure

•Permalloy films with various crystallite sizes were made by magnetron sputtering.•New effect of a sharp broadening and shift of ferromagnetic resonance line is found.•The revealed effect is of the threshold nature.•The effect occurs when the crystallite size is greater than the critical value.•The...

Full description

Saved in:
Bibliographic Details
Published in:Journal of alloys and compounds 2022-04, Vol.900, p.163416, Article 163416
Main Authors: Izotov, A.V., Belyaev, B.A., Boev, N.M., Burmitskikh, A.V., Skomorokhov, G.V., Zharkov, S.M., Solovev, P.N.
Format: Article
Language:English
Subjects:
Crystallites
Damping
Electronic devices
Energy dissipation
Energy transfer
Ferromagnetic materials
Ferromagnetic resonance
Ferromagnetic resonance (FMR)
Ferrous alloys
Line broadening
Magnetic alloys
Magnetic films
Magnetic structure
Magnetic thin films
Magnetization
Magnetization ripple
Magnons
Micromagnetic simulation
Nanocrystallite
Nanocrystals
Resonance lines
Thick films
Thin films
Two-magnon scattering process
Citations: Items that this one cites
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:•Permalloy films with various crystallite sizes were made by magnetron sputtering.•New effect of a sharp broadening and shift of ferromagnetic resonance line is found.•The revealed effect is of the threshold nature.•The effect occurs when the crystallite size is greater than the critical value.•The effect is caused by two-magnon scattering of spin waves on magnetic structure. [Display omitted] With the rapid development of telecommunication technologies and highly integrated electronic devices, researchers show great interest in nanocrystalline soft magnetic thin films with unique characteristics for microwave applications. An important direction of the current research in this field is the study of high-frequency magnetization dynamics that directly depends on the damping processes in a magnetic medium. This paper reports on the effect of sharp broadening and shift of the ferromagnetic resonance (FMR) line revealed experimentally in a 40-nm-thick nanocrystalline permalloy (Fe20Ni80) thin film at a frequency of about 5 GHz. The effect arises only in films with crystallite size exceeding some critical value Dcr. The micromagnetic simulation demonstrates that exchange and dipolar interactions between randomly oriented crystallites form in the film a quasiperiodic magnetic structure with a characteristic wavelength in the range from 36 nm to 3.3 µm. An analysis of the two-magnon scattering model and simulation results shows that the formed magnetic structure provides the energy transfer from uniform magnetization oscillations (uniform FMR) to spin waves, which results in an additional energy dissipation channel and, consequently, sharp FMR line broadening. A theoretical estimate of the critical crystallite size Dcr based on this model yields a value of ~14.3 nm for 40-nm-thick Fe20Ni80 films.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2021.163416