Alsem, D.H.

Boerma, D.O.

Chechenin, N.G.

Chezan, A.R.

Craus, C.B.

Hosson, J.Th.M. De

Niesen, L.

Vystavel, T.

English

ARTS repository - University of Groningen

   University of GroningenRelation between observed micromagnetic ripple and FMR width in ultrasoft magnetic filmsChechenin, N.G.; Chezan, A.R.; Craus, C.B.; Vystavel, T.; Alsem, D.H.; Boerma, D.O.;Hosson, J.Th.M. De; Niesen, L.Published in:2002 IEEE International Magnetics Conference, 2002. INTERMAG Europe 2002. Digest of Technical PapersIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:2002Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Chechenin, N. G., Chezan, A. R., Craus, C. B., Vystavel, T., Alsem, D. H., Boerma, D. O., Hosson, J. T. M.D., & Niesen, L. (2002). Relation between observed micromagnetic ripple and FMR width in ultrasoftmagnetic films. In 2002 IEEE International Magnetics Conference, 2002. INTERMAG Europe 2002. Digestof Technical Papers (pp. BU 15-BU 15). University of Groningen, The Zernike Institute for AdvancedMaterials.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 06-06-2022BU 15 RELATION BETWEEN OBSERVED MICROMAGNETIC RIPPLE AND FMR WIDTH IN ULTRASOFT MAGNETIC FILMS N. G. Chechenin, A.R. Chezan, C.B. Craus, T. Vystavel, D. H. Alsem, D. 0. Boenna, J.Th.M.De Hosson and L. Niesen Marerials Science Center, University of Groningen, Nijenborgh 4, NL-9747 A G Groningen, Netherlands, tel. 050-363 4822, fax: 050-363-3471, e-mail: Chechenin@phys. mg.nl It was demonstrated that nanocrystalline FeXN films (X is an alloying element), obtained by sputtering or electrodeposition, have excellent ultra-soft magnetic properties with a saturation magnetization up to M ~ 2 . 0  T, a high magnetic susceptibility and a frequency range above 1 GHz. Here we report on a correlation between the microstructure, the micromagnetic ripples, and high frequency magnetism in the sputter-deposited FeZrN-films. The mnge of opemting frequencies fo r  the films is limited by the frequency of the ferromagnetic resonance (FMR) and by the width of FMR. Besides contributions to the FMR width due to dissipation sources, which are characteristic f o r  crystalline and polyciystalline ferromagnetics, in nanocrystalline films there exists an additional contribution due to the local variation of the magnetic uniaxial anisotropy. Notwithstanding its importance, so far  only a very few studies have been reported in literature. The variation of the local anisotropy causes a magnetic ripple structure that can be observed with the Lorentz electron microscopy (LTEM) [I]. The coupling volume and the angular spread <q2>lR of the magnetic ripples are obtained from an analysis of the wavelength and angular distributions of the LTEM image ripples, as based on a Fourier analysis of the image. This was done f o r  films with different thickness, gmin size and microstructure, as illustrated by Fig.l. The effect of the ripples on the FMR width is analyzed using an approach based on the Fig.l. The microstmcture and Landau-Lifshitz equation without the dissipative tenn. ripple fortwo different films. The local dispersion of the magnetization gives nse to a stray field 121. In our approach we assume that this fluctuating stray field is a major cause of the broadening of the FMR-line. A strong dependence of the resonance width on the magnetic moment dispersion, Afdfo = 32<Q2>2(dM)2/A, is predicted by such an approach, where d is the film thickness and A is the exchange stiffness. W e  show that to a large extent this particular aspect can explain the width of the resonance frequency in ourfilms. References: 1. N.G. Chechenin, A.R. Chezan, C.B. Craus, T. Vystavel, D. 0. Boerma, J.Th.M.De Hosson and L. Niesen, J. Magn. Magn. Mater., (2002), accepted 2. H.Hoffmann, J. Appl. Phys., 35 (1964)1790-8; Thin Solid Films, 58 (1979) 223-33 BU 16 MOMENT REDUCTION DUE TO OXYGEN CONTAMINATION OF Fe35CoE5 Winnie  Yu", James  A. Bairi, Yingguo Peng, David E. Laughlin Dtda Stomge S:yste,ris Center, Carrregie Mellon Uriiucrsity, Pittsburgh, PA, 15213, USA 'Ph: 4 12-%68-.1824, FAX: 412-268-3497, cniail: ~n~~c@!?aridre~cu. c iiu. d i e  Obtaining high moment sputtered thin filiiis with soft properties reqiiires small grains with good exchange coupling be- t s w n  the grains. Cotit.aniiiiat,ioii of graiii boundaries duiing deposition will signifi- cantly degrade magnetic softness and re- duce magnetic moment. In this work, we report oil such containination induced by siihst,ratt? bias diiririg spu ttrr dc~positioii of Fc35C065 iilins. FexsCoRs films (thickness: 100 nm) . _. J 0Vblas ' -  - "  Fzgure 1 Dzffructzon zmuges of Fe,iCoes .. .. were sputtered at  100 W target power iil 3 mTorr of Ar, with varying substrate bias from 0 V to -300 V. The niasiniuni value of moment of 2.35 T was observed at  iiiterniediatr bias valiies: but the saturation magiietization of the films decreased nearly 10% for the samples at. the highest bias. TEM analysis of the samples indicat.cd an increase in c i s i d c  ronteiit, and a decrease of grain diameter from 75 nin tn  25 r i m  with inrrcasing subst,rate bias. The increase in oxide can be seen in the TEM analysis shown in Figure 1 in which the intensity of the oxide diffraction rings is 8% stronger in the -300 V bias sample than in the 0 V bias sample. The loss of rnaguetization with i qnantitatively consistcnt with a 100 80 iioiiin;tgrietic oside shrll of approximately 1 nrii in thickness arourid each grain for a11 biases. This is illustrated in Figure 2, which shows the expected moment loss (calculated) as a function of grain size 8 for such a microstructure for four different shell E 6o thickiiesses Thc grain and shell structuie is shown 4o in an inset in  the figure The cffect 15 simply that of increasing surface to volume ratio as the grains 20 get smaller Note that the measured magnetiza- tions and grain sues are all consistent with a 1 nm OO 20 40 60 80 100 thick shell Importantly nri would expect A non- hienk nvhaiige ( oiiplmg hctwceii thr grains and yield very poor soft properties. This was observed in these samples, as their predicted coercivity due to magnetization ripple is much lower than what was observed Grain diameter, d (nm) l7ldtqilPf li 211('11 i ) f  1 hi5 t h l c h l l C \ 5  113 lJ(' S l I f f l L l C l l ~  1 0  Flguw 2 Moment us (/ru?n dwrtete? 

Relation between observed micromagnetic ripple and FMR width in ultrasoft magnetic films

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Relation between observed micromagnetic ripple and FMR width in ultrasoft magnetic films

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