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Impedance of nanometer thickness ferromagnetic Co40Fe40B20 films.

Jen SU, Chou TY, Lo CK - Nanoscale Res Lett (2011)

Bottom Line: In the h//w case, IM spectra show QFMR-K at F0 and FMR-W at Fn.We find that f0 and F0 are shifted from fFMRK, respectively, and fn = Fn.The in-plane spin-wave resonances are responsible for those relative shifts.PACS No. 76.50.+q; 84.37.+q; 75.70.-i.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Physics, Academia Sinica, Taipei, Taiwan, 11529, Republic of China. physjen@gate.sinica.edu.tw.

ABSTRACT
Nanocrystalline Co40Fe40B20 films, with film thickness tf = 100 nm, were deposited on glass substrates by the magnetron sputtering method at room temperature. During the film deposition period, a dc magnetic field, h = 40 Oe, was applied to introduce an easy axis for each film sample: one with h//L and the other with h//w, where L and w are the length and width of the film. Ferromagnetic resonance (FMR), ultrahigh frequency impedance (IM), dc electrical resistivity (ρ), and magnetic hysteresis loops (MHL) of these films were studied. From the MHL and r measurements, we obtain saturation magnetization 4πMs = 15.5 kG, anisotropy field Hk = 0.031 kG, and r = 168 mW.cm. From FMR, we can determine the Kittel mode ferromagnetic resonance (FMR-K) frequency fFMRK = 1,963 MHz. In the h//L case, IM spectra show the quasi-Kittel-mode ferromagnetic resonance (QFMR-K) at f0 and the Walker-mode ferromagnetic resonance (FMR-W) at fn, where n = 1, 2, 3, and 4. In the h//w case, IM spectra show QFMR-K at F0 and FMR-W at Fn. We find that f0 and F0 are shifted from fFMRK, respectively, and fn = Fn. The in-plane spin-wave resonances are responsible for those relative shifts.PACS No. 76.50.+q; 84.37.+q; 75.70.-i.

No MeSH data available.


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Permeability μ = μR + i μI. Permeability μ = μR + iμI where μR and μI are the real and imaginary parts of the film samples vs. the frequency f.
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Figure 5: Permeability μ = μR + i μI. Permeability μ = μR + iμI where μR and μI are the real and imaginary parts of the film samples vs. the frequency f.

Mentions: Moreover, if we take the formula Z = (B/As)(1 + i)coth[(t/2As)(1 + i)], where B = (ρL)/(2w), As = [ρ/(πfξμo)][cos(δ/2) + isin(δ/2)], μ ≡ ξμo, and μo = 4π × 10-7 H/m. By using the Newton-Raphson method [12], we may calculate the f dependence of μR ≡ ξcosδ or μI ≡ -ξsinδ from the R and X data. From the μR vs. f or the μI vs. f plot, as shown in Figure 5, we can define the cutoff frequency fc = 2,051 MHz in the h//L case. Clearly, fc in Figure 5 is almost equal to f0 found in Figure 3.


Impedance of nanometer thickness ferromagnetic Co40Fe40B20 films.

Jen SU, Chou TY, Lo CK - Nanoscale Res Lett (2011)

Permeability μ = μR + i μI. Permeability μ = μR + iμI where μR and μI are the real and imaginary parts of the film samples vs. the frequency f.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211980&req=5

Figure 5: Permeability μ = μR + i μI. Permeability μ = μR + iμI where μR and μI are the real and imaginary parts of the film samples vs. the frequency f.
Mentions: Moreover, if we take the formula Z = (B/As)(1 + i)coth[(t/2As)(1 + i)], where B = (ρL)/(2w), As = [ρ/(πfξμo)][cos(δ/2) + isin(δ/2)], μ ≡ ξμo, and μo = 4π × 10-7 H/m. By using the Newton-Raphson method [12], we may calculate the f dependence of μR ≡ ξcosδ or μI ≡ -ξsinδ from the R and X data. From the μR vs. f or the μI vs. f plot, as shown in Figure 5, we can define the cutoff frequency fc = 2,051 MHz in the h//L case. Clearly, fc in Figure 5 is almost equal to f0 found in Figure 3.

Bottom Line: In the h//w case, IM spectra show QFMR-K at F0 and FMR-W at Fn.We find that f0 and F0 are shifted from fFMRK, respectively, and fn = Fn.The in-plane spin-wave resonances are responsible for those relative shifts.PACS No. 76.50.+q; 84.37.+q; 75.70.-i.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Physics, Academia Sinica, Taipei, Taiwan, 11529, Republic of China. physjen@gate.sinica.edu.tw.

ABSTRACT
Nanocrystalline Co40Fe40B20 films, with film thickness tf = 100 nm, were deposited on glass substrates by the magnetron sputtering method at room temperature. During the film deposition period, a dc magnetic field, h = 40 Oe, was applied to introduce an easy axis for each film sample: one with h//L and the other with h//w, where L and w are the length and width of the film. Ferromagnetic resonance (FMR), ultrahigh frequency impedance (IM), dc electrical resistivity (ρ), and magnetic hysteresis loops (MHL) of these films were studied. From the MHL and r measurements, we obtain saturation magnetization 4πMs = 15.5 kG, anisotropy field Hk = 0.031 kG, and r = 168 mW.cm. From FMR, we can determine the Kittel mode ferromagnetic resonance (FMR-K) frequency fFMRK = 1,963 MHz. In the h//L case, IM spectra show the quasi-Kittel-mode ferromagnetic resonance (QFMR-K) at f0 and the Walker-mode ferromagnetic resonance (FMR-W) at fn, where n = 1, 2, 3, and 4. In the h//w case, IM spectra show QFMR-K at F0 and FMR-W at Fn. We find that f0 and F0 are shifted from fFMRK, respectively, and fn = Fn. The in-plane spin-wave resonances are responsible for those relative shifts.PACS No. 76.50.+q; 84.37.+q; 75.70.-i.

No MeSH data available.


Related in: MedlinePlus