Investigation of the Structure of Ferromagnetic Films by Means of the Differential Susceptibility

Kempter, K.; Hoffmann, H.

doi:10.1002/pssb.19690340123

Cited by 54 publications

(8 citation statements)

References 16 publications

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“…18,19 In particular, the b coefficient yields valuable physical information about the local anisotropy constant K loc of a random distribution of local easy axes. [42][43][44] For 3d ions in amorphous materials, K loc can be 19,44 in the range 10 5 J/m 3 ϽK loc р10 6 J/m 3 corresponding to correlation lengths of 2 nmϾdу0.25 nm. Note that dϷ0.25 nm is related to the atomic volume V in the framework of the Harris-Plischke-Zuckermann ͑HPZ͒ model 45 for amorphous magnetism.…”

Section: Transversely Biased Initial Susceptibilitymentioning

confidence: 99%

Perpendicular anisotropy detected by transversely biased initial susceptibility via the magneto-optic Kerr effect inFexSi1−x<

et al. 1997

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We studied experimentally and theoretically the perpendicular anisotropy and the stripe-domain structure in both Fe x Si 1Ϫx thin films and Fe x Si 1Ϫx /Si multilayers, the latter being in the low-modulation-length regime (0.4 nmϽϽ7 nm). The experimental study was made by means of the transversely biased initial susceptibility t␤ via the magneto-optic Kerr effect. The samples under study were prepared by dc triode sputtering at T S ϭ300 K. It is found that the appearance of stripe domains is more pronounced for decreasing as x remains constant and may be caused by both the increase in effective magnetic thickness and the reduction in effective magnetization as decreases. For multilayers with ϭ0.4 nm, the observed field dependence of t␤ Ϫ1 is similar to that found in homogeneous thin films when weak stripe-domain structures arise as a consequence of the existence of perpendicular anisotropy K N . We propose a quasistatic one-dimensional model to explain the behavior of t␤ Ϫ1 when stripe domains are present, and we analyze the critical occurrence of stripe domains. We calculated the so-called pseudo-uniaxial anisotropy field H Ks , associated with the stripes, in two extreme cases: exchange-driven susceptibility or magnetic free poles ͑nonzero divergence in the bulk͒. The latter case agrees better with experiment. We found that perpendicular anisotropy is not exclusive of a well-defined multilayer structure; i.e., K N arises even when there are no interfaces in the volume. By setting the experimental saturation field H s ͑obtained by hysteresis loops͒ into our model, we obtain both the perpendicular anisotropy constant K N ϭ10 4 -10 5 J/m 3 and the critical thickness t c for the occurrence of a stripe-domain structure. Some possible sources of perpendicular anisotropy are discussed, for example, the associated isotropic compressive stress , whose contribution is found to be ͉K N ͉ magnetoel Ϸ1.5-4.5ϫ10 4 J/m 3 .

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Section: Transversely Biased Initial Susceptibilitymentioning

confidence: 99%

Perpendicular anisotropy detected by transversely biased initial susceptibility via the magneto-optic Kerr effect inFexSi1−x<

et al. 1997

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“…The measured permeability is slightly lower than the dc permeability . This disagreement may be attributed to the dispersion of anisotropy in the film [7], [8].…”

Section: A Magnetic Propertiesmentioning

confidence: 89%

Soft magnetic properties and microstructure of high moment Fe-N-Al-O films for recording heads

et al. 2000

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Fe-N-Al-O alloy films were fabricated by rf reactive sputtering in a mixed Ar+N 2 plasma. The Al and O contents in films were varied by the area ratio of Al 2 O 3 chips placed on an Fe target. We examined the effects of additional elements, such as Al and O, on magnetic and electrical properties of the Fe-N-Al-O films, and we investigated the relationship between soft magnetic properties and microstructure. The permeability reaches a maximum of about 1800, when the Al+O content range is 10-16 at%. Fe-N-Al-O films in this range have 4 Ms = 19-20 kG and = 60-100 cm. The real part of permeability ( ) of the 0.7-m-thick Fe 79 N 5 Al 6 O 10 film remains constant up to 300 MHz. The as-deposited Fe-N-Al-O film showing soft magnetic properties has homogeneous microstructure with a grain size of about 5 nm. It seems that the addition of Al and O to Fe-N films is effective in suppressing grain growth, and contributes to the formation of homogeneous film structure.

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“…From the data, we get H K1,ʈ = 770 A / m ͑9.7 Oe͒ and H K2,Ќ = 1240 A / m ͑15.6 Oe͒ for the case ͑H x , h y ͒, and H K1,Ќ = 420 A / m ͑5.3 Oe͒ and H K2,ʈ = 1650 A / m ͑20.7 Oe͒ for the case ͑H y , h x ͒.For a perfect uniaxial anisotropy layer, the linear extrapolations should cross the H axis at the same values ͑H K,ʈ = H K,Ќ ͒, but here a strong difference between the two values is observed. This is commonly attributed to magnetization dispersion,26 which is verified here as the dispersion was indeed created in the sample. The estimated anisotropy fields, empirically derived from the average of H K,ʈ and H K,Ќ calculated either from the linear relations or from the extrapolations to the applied field axis, are H K1 = 595 A / m and H K2 = 1445 A / m. Nevertheless, it is impossible to describe the f r 2 dependence for the configurations ͑H x , h y ͒ and ͑H y , h x ͒ with the same set of values of H K 1 and H K 2 .…”

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confidence: 90%

Magnetization dynamics of soft films with thickness-dependent anisotropy

et al. 2009

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The static and dynamic magnetic properties of samples consisting of two soft magnetic layers with in-plane easy axes at right angles are studied by micromagnetics and experiments. A one-dimensional micromagnetic model is developed, and solved quasianalytically for statics and dynamics. In particular, it is shown that the magnetic permeability arises from a set of eigenmodes, each with a macrospin ͑or gyromagnetic͒ response, that are excited differently depending on ac field orientation. Experiments ͑magnetization curves, permeability under field and in several directions͒ on cobalt-based amorphous alloy bilayers are well reproduced by the model with a single set of parameters. Such samples are therefore model one-dimensional nonuniform magnetic systems, simple yet with a rich behavior, for statics and dynamics.

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Investigation of the Structure of Ferromagnetic Films by Means of the Differential Susceptibility

Cited by 54 publications

References 16 publications

Perpendicular anisotropy detected by transversely biased initial susceptibility via the magneto-optic Kerr effect inFexSi1−x<

Perpendicular anisotropy detected by transversely biased initial susceptibility via the magneto-optic Kerr effect inFexSi1−x<

Soft magnetic properties and microstructure of high moment Fe-N-Al-O films for recording heads

Magnetization dynamics of soft films with thickness-dependent anisotropy

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