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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.


Related in: MedlinePlus

(a) TR-MOKE traces at three different doses. Here, symbols correspond to the experimental data and solid curves are fits to Equation 2. (b) Damping is plotted as a function of dose. The shaded box represents the transion between two regions. (c) Variation of damping with dose in the lower dose regime for NiFe/Pt (filled circles) and NiFe/Cu (filled triangles). Here, symbols are the experimental results and solid lines are linear fits. The data shown in Fig. 3 (a–c) correspond to H = 1.8 kOe. (d) Variation of damping with precession frequency at three different doses.
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f3: (a) TR-MOKE traces at three different doses. Here, symbols correspond to the experimental data and solid curves are fits to Equation 2. (b) Damping is plotted as a function of dose. The shaded box represents the transion between two regions. (c) Variation of damping with dose in the lower dose regime for NiFe/Pt (filled circles) and NiFe/Cu (filled triangles). Here, symbols are the experimental results and solid lines are linear fits. The data shown in Fig. 3 (a–c) correspond to H = 1.8 kOe. (d) Variation of damping with precession frequency at three different doses.

Mentions: The influence of interfacial engineering on the precession and damping of NiFe/Pt bilayers is shown in Fig. 3(a). For the lowest irradiation dose (d = 0.3 pC/μm2) a value of α = 0.042 was obtained, while for an intermediate dose, d = 2.0 pC/μm2, α increased to a maximum of 0.060 before falling again to α = 0.052 for the largest dose, d = 3.3 pC/μm2.


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) TR-MOKE traces at three different doses. Here, symbols correspond to the experimental data and solid curves are fits to Equation 2. (b) Damping is plotted as a function of dose. The shaded box represents the transion between two regions. (c) Variation of damping with dose in the lower dose regime for NiFe/Pt (filled circles) and NiFe/Cu (filled triangles). Here, symbols are the experimental results and solid lines are linear fits. The data shown in Fig. 3 (a–c) correspond to H = 1.8 kOe. (d) Variation of damping with precession frequency at three different doses.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f3: (a) TR-MOKE traces at three different doses. Here, symbols correspond to the experimental data and solid curves are fits to Equation 2. (b) Damping is plotted as a function of dose. The shaded box represents the transion between two regions. (c) Variation of damping with dose in the lower dose regime for NiFe/Pt (filled circles) and NiFe/Cu (filled triangles). Here, symbols are the experimental results and solid lines are linear fits. The data shown in Fig. 3 (a–c) correspond to H = 1.8 kOe. (d) Variation of damping with precession frequency at three different doses.
Mentions: The influence of interfacial engineering on the precession and damping of NiFe/Pt bilayers is shown in Fig. 3(a). For the lowest irradiation dose (d = 0.3 pC/μm2) a value of α = 0.042 was obtained, while for an intermediate dose, d = 2.0 pC/μm2, α increased to a maximum of 0.060 before falling again to α = 0.052 for the largest dose, d = 3.3 pC/μm2.

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