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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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Impedance Z = R + iX with  // L. Impedance Z = R + iX where R and X are the resistance and reactance of the Co40Fe40B20 film sample with //L. f0 and fn, with n = 1, 2, 3, 4, are the frequency peaks associated with various kinds of resonances.
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Figure 3: Impedance Z = R + iX with // L. Impedance Z = R + iX where R and X are the resistance and reactance of the Co40Fe40B20 film sample with //L. f0 and fn, with n = 1, 2, 3, 4, are the frequency peaks associated with various kinds of resonances.

Mentions: In order to interpret the IM data (or spectrum) of this work, as shown in Figure 3 (the h//L case) and in Figure 4 (the h//w case), we have the following definitions. First, whenever there is a resonance event, we should find a peak located at f = f0 and f = fn, where n = 1, 2, 3, 4 in the R-spectrum, and a wiggle (or oscillation) centered around the same f0 and fn in the X-spectrum. To summarize the data in Figures 3 and 4, we have in the h//L case, f0 = 2,081, f1 = 1,551, f2 = 1,291, f3 = 991, and f4 = 781 MHz; and in the h//w case, F0 = 2,431, F1 = 1,551, F2 = 1,281, F3 = 991, and F4 = 721 MHz. From these experimental facts, we reach two conclusions: (1) f0 ≠ F0 and (2) within errors, fn = Fn. Since at either f0 or F0, each corresponding wiggle crosses zero, we believe there is a quasi-FMR-K event. Notice for the moment that because f0 ≠ F0, we use the prefix "quasi" to describe the event. More explanation will be given later.


Impedance of nanometer thickness ferromagnetic Co40Fe40B20 films.

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

Impedance Z = R + iX with  // L. Impedance Z = R + iX where R and X are the resistance and reactance of the Co40Fe40B20 film sample with //L. f0 and fn, with n = 1, 2, 3, 4, are the frequency peaks associated with various kinds of resonances.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Impedance Z = R + iX with // L. Impedance Z = R + iX where R and X are the resistance and reactance of the Co40Fe40B20 film sample with //L. f0 and fn, with n = 1, 2, 3, 4, are the frequency peaks associated with various kinds of resonances.
Mentions: In order to interpret the IM data (or spectrum) of this work, as shown in Figure 3 (the h//L case) and in Figure 4 (the h//w case), we have the following definitions. First, whenever there is a resonance event, we should find a peak located at f = f0 and f = fn, where n = 1, 2, 3, 4 in the R-spectrum, and a wiggle (or oscillation) centered around the same f0 and fn in the X-spectrum. To summarize the data in Figures 3 and 4, we have in the h//L case, f0 = 2,081, f1 = 1,551, f2 = 1,291, f3 = 991, and f4 = 781 MHz; and in the h//w case, F0 = 2,431, F1 = 1,551, F2 = 1,281, F3 = 991, and F4 = 721 MHz. From these experimental facts, we reach two conclusions: (1) f0 ≠ F0 and (2) within errors, fn = Fn. Since at either f0 or F0, each corresponding wiggle crosses zero, we believe there is a quasi-FMR-K event. Notice for the moment that because f0 ≠ F0, we use the prefix "quasi" to describe the event. More explanation will be given later.

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