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Tunable Magnetization Dynamics in Interfacially Modified Ni81Fe19/Pt Bilayer Thin Film Microstructures.

Ganguly A, Azzawi S, Saha S, King JA, Rowan-Robinson RM, Hindmarch AT, Sinha J, Atkinson D, Barman A - Sci Rep (2015)

Bottom Line: Magnetization precession was fitted with a single-mode damped sinusoid to extract the Gilbert damping parameter.This is interpreted in terms of both intrinsic effects and extrinsic two-magnon scattering effects resulting from the expansion of the interfacial region and the creation of a compositionally graded alloy.The results suggest a new direction for the control of precessional magnetization dynamics, and open the opportunity to optimize high-speed magnetic devices.

View Article: PubMed Central - PubMed

Affiliation: Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sec. III, Salt Lake, Kolkata 700098, India.

ABSTRACT
Interface modification for control of ultrafast magnetic properties using low-dose focused ion beam irradiation is demonstrated for bilayers of two technologically important materials: Ni81Fe19 and Pt. Magnetization dynamics were studied using an all-optical time-resolved magneto-optical Kerr microscopy method. Magnetization relaxation, precession, damping and the spatial coherence of magnetization dynamics were studied. Magnetization precession was fitted with a single-mode damped sinusoid to extract the Gilbert damping parameter. A systematic study of the damping parameter and frequency as a function of irradiation dose varying from 0 to 3.3 pC/μm(2) shows a complex dependence upon ion beam dose. This is interpreted in terms of both intrinsic effects and extrinsic two-magnon scattering effects resulting from the expansion of the interfacial region and the creation of a compositionally graded alloy. The results suggest a new direction for the control of precessional magnetization dynamics, and open the opportunity to optimize high-speed magnetic devices.

No MeSH data available.


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(a) Comparison of TR-MOKE traces between NiFe/Pt (d = 0.3 pC/μm2) and NiFe films. Symbols correspond to experimental data while the solid curves are fits to Equation 2. (b) Power spectra of NiFe/Pt sample at different bias field values H. (c) Frequency vs. bias magnetic field for the NiFe/Pt (d = 0.3 pC/μm2) sample. Here the symbols represent experimental data points and the solid curve is a fit to Equation 3.
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f2: (a) Comparison of TR-MOKE traces between NiFe/Pt (d = 0.3 pC/μm2) and NiFe films. Symbols correspond to experimental data while the solid curves are fits to Equation 2. (b) Power spectra of NiFe/Pt sample at different bias field values H. (c) Frequency vs. bias magnetic field for the NiFe/Pt (d = 0.3 pC/μm2) sample. Here the symbols represent experimental data points and the solid curve is a fit to Equation 3.

Mentions: A bi-exponential background was subtracted from the TR-MOKE traces to isolate the damped precessional behavior. Precessional data for a bilayer structure irradiated with d = 0.3 pC/μm2 and uncapped NiFe film at H = 1.8 kOe are presented in Fig. 2(a). In both cases a single frequency damped oscillation is clear and the decay is much faster for the bilayer film. Similar single frequency damped oscillatory behaviour was obtained for all of the samples here, see Fig. 1(c) for further examples. The time domain data were fitted with a damped sine curve:


Tunable Magnetization Dynamics in Interfacially Modified Ni81Fe19/Pt Bilayer Thin Film Microstructures.

Ganguly A, Azzawi S, Saha S, King JA, Rowan-Robinson RM, Hindmarch AT, Sinha J, Atkinson D, Barman A - Sci Rep (2015)

(a) Comparison of TR-MOKE traces between NiFe/Pt (d = 0.3 pC/μm2) and NiFe films. Symbols correspond to experimental data while the solid curves are fits to Equation 2. (b) Power spectra of NiFe/Pt sample at different bias field values H. (c) Frequency vs. bias magnetic field for the NiFe/Pt (d = 0.3 pC/μm2) sample. Here the symbols represent experimental data points and the solid curve is a fit to Equation 3.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664935&req=5

f2: (a) Comparison of TR-MOKE traces between NiFe/Pt (d = 0.3 pC/μm2) and NiFe films. Symbols correspond to experimental data while the solid curves are fits to Equation 2. (b) Power spectra of NiFe/Pt sample at different bias field values H. (c) Frequency vs. bias magnetic field for the NiFe/Pt (d = 0.3 pC/μm2) sample. Here the symbols represent experimental data points and the solid curve is a fit to Equation 3.
Mentions: A bi-exponential background was subtracted from the TR-MOKE traces to isolate the damped precessional behavior. Precessional data for a bilayer structure irradiated with d = 0.3 pC/μm2 and uncapped NiFe film at H = 1.8 kOe are presented in Fig. 2(a). In both cases a single frequency damped oscillation is clear and the decay is much faster for the bilayer film. Similar single frequency damped oscillatory behaviour was obtained for all of the samples here, see Fig. 1(c) for further examples. The time domain data were fitted with a damped sine curve:

Bottom Line: Magnetization precession was fitted with a single-mode damped sinusoid to extract the Gilbert damping parameter.This is interpreted in terms of both intrinsic effects and extrinsic two-magnon scattering effects resulting from the expansion of the interfacial region and the creation of a compositionally graded alloy.The results suggest a new direction for the control of precessional magnetization dynamics, and open the opportunity to optimize high-speed magnetic devices.

View Article: PubMed Central - PubMed

Affiliation: Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sec. III, Salt Lake, Kolkata 700098, India.

ABSTRACT
Interface modification for control of ultrafast magnetic properties using low-dose focused ion beam irradiation is demonstrated for bilayers of two technologically important materials: Ni81Fe19 and Pt. Magnetization dynamics were studied using an all-optical time-resolved magneto-optical Kerr microscopy method. Magnetization relaxation, precession, damping and the spatial coherence of magnetization dynamics were studied. Magnetization precession was fitted with a single-mode damped sinusoid to extract the Gilbert damping parameter. A systematic study of the damping parameter and frequency as a function of irradiation dose varying from 0 to 3.3 pC/μm(2) shows a complex dependence upon ion beam dose. This is interpreted in terms of both intrinsic effects and extrinsic two-magnon scattering effects resulting from the expansion of the interfacial region and the creation of a compositionally graded alloy. The results suggest a new direction for the control of precessional magnetization dynamics, and open the opportunity to optimize high-speed magnetic devices.

No MeSH data available.


Related in: MedlinePlus