Temperature induced ferromagnetic resonance frequency change and resonance line broadening of a Fe-Co-Hf-N film with in-plane uniaxial anisotropy - a theoretical and experimental study

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:369

Article

Seemann, K.¹  Krueger, K.¹  Leiste, H.¹ 

[1] Karlsruhe Inst Technol KIT, Inst Appl Mat, D-76344 Eggenstein Leopoldshafen, Germany

关键词: Ferromagnetic film;    Temperature-dependent FMR;    Line broadening;    Intrinsic damping;   

DOI  :  10.1016/j.jmmm.2014.06.022

来源: Elsevier

【 摘 要 】

A soft ferromagnetic Fe-Co-Hf-N film was produced by reactive r.f, magnetron sputtering, in order to study its high-frequency behaviour by means of frequency domain permeability measurements up to the GHz range. It resulted in the composition Fe33Co43Hf10N14 and exhibits a saturation polarisation J(s) of around 1.35 T. The film is consequently considered as being uniformly magnetised due to an in-plane uniaxial anisotropy of approximately mu(0).H-u approximate to 4.5 mT after annealing it at 400 degrees C in a static magnetic field for 1 h. While heating the Film from room temperature to 300 degrees C during the high-frequency measurement procedure a marked ferromagnetic resonance peak shift (maximum of the imaginary part of the frequency-dependent permeability) from 2.35 GHz down to 1.84 GHz is conspicuous. This is in a very good agreement with the theory established by taking the real ferromagnetic resonance formula for ferromagnetic films into account. Simultaneously, the full width at half maximum (FWHM) Delta f(FMR) of the resonance line, which is a consequence of precession damping of the magnetic moments, clearly increases. This behaviour does not correlate with the ferromagnetic resonance value decrease, and is qualitatively discussed in terms of exchange interaction with the intrinsic spin-lattice relaxation process due to not totally supressed orbital momenta (< L > not equal 0) of Fe2+ and Co2+ or the occupation change of their spectral levels within the induced uniaxial anisotropy field. (C) 2014 Elsevier B.V.. All rights reserved.

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