title: Tunable Magnetization Dynamics in Interfacially Modified Ni81Fe19/Pt Bilayer Thin Film Microstructures.
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.
authors.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.
authors.forename: Arnab
authors.initials: A
authors.lastname: Ganguly
authors.affiliation: Department of Physics, Durham University, Durham, DH1 3LE, United Kingdom.
authors.forename: Sinan
authors.initials: S
authors.lastname: Azzawi
authors.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.
authors.forename: Susmita
authors.initials: S
authors.lastname: Saha
authors.affiliation: Department of Physics, Durham University, Durham, DH1 3LE, United Kingdom.
authors.forename: J A
authors.initials: JA
authors.lastname: King
authors.affiliation: Department of Physics, Durham University, Durham, DH1 3LE, United Kingdom.
authors.forename: R M
authors.initials: RM
authors.lastname: Rowan-Robinson
authors.affiliation: Department of Physics, Durham University, Durham, DH1 3LE, United Kingdom.
authors.forename: A T
authors.initials: AT
authors.lastname: Hindmarch
authors.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.
authors.forename: Jaivardhan
authors.initials: J
authors.lastname: Sinha
authors.affiliation: Department of Physics, Durham University, Durham, DH1 3LE, United Kingdom.
authors.forename: Del
authors.initials: D
authors.lastname: Atkinson
authors.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.
authors.forename: Anjan
authors.initials: A
authors.lastname: Barman