Time-Domain Study of Magnetization Dynamics in Magnetic Thin Films and Micro- and Nanostructures

Novel magnetic structures with precisely controlled dimensions and shapes at the nanoscale have potential applications in spin logic, spintronics and other spin-based communication devices. We report the fabrication of two-dimensional bi-structure magnonic crystal in the form of embedded nanodots in a periodic Ni80Fe20 antidot lattice structure (annular antidot) by focused ion-beam lithography. The spin-wave spectra of the annular antidot sample,studied for the first time by a time-resolved magneto-optic Kerr effect microscopy show a remarkable variation with bias field, which is important for the above device applications. The optically induced spin-wave spectra show multiple modes in the frequency range 14.7 GHz to 3.5 GHz due to collective interactions between the dots and antidots as well as the annular elements within the whole array. Numerical simulations qualitatively reproduce the experimental results, and simulated mode profiles reveal the spatial distribution of the spin-wave modes and internal magnetic fields responsible for these observations. It is observed that the internal field strength increases by about 200 Oe inside each dot embedded within the hole of annular antidot lattice as compared to pure antidot lattice and pure dot lattice. The stray field for the annular antidot lattice is found to be significant (0.8kOe) as opposed to the negligible values of the same for the pure dot lattice and pure antidot lattice. Our findings open up new possibilities for development of novel artificial crystals.

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“…The TR-MOKE microscope used in our investigation is based upon two-colour collinear optical pump-probe geometry [41].…”

Section: Methodsmentioning

confidence: 99%

All optical detection of picosecond spin-wave dynamics in 2D annular antidot lattice

Porwal

Mondal

Choudhury

et al. 2018

J. Phys. D: Appl. Phys.

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“…All these techniques primarily rely on electrical excitation, detection and extremely delicate micro-fabrication [26]. Recently, it has been demonstrated that by using time resolved magneto-optical Kerr effect (TRMOKE) [27] technique SHA can be measured more conveniently in a non-invasive manner without the requirement of advanced microfabrication and electrical detection, and more precise estimate of SHA may be obtained [28].…”

Section: Introductionmentioning

confidence: 99%

All-optical detection of the spin Hall angle inW/CoFeB/SiO2heterostructures with varying thickness of the tungsten layer

et al. 2017

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The development of advanced spintronics devices hinges on the efficient generation and utilization of pure spin current. In materials with large spin-orbit coupling, the spin Hall effect may convert charge current to pure spin current and a large conversion efficiency, which is quantified by spin Hall angle (SHA), is desirable for the realization of miniaturized and energy efficient spintronic devices. Here, we report a giant SHA in beta-tungsten (β-W) thin films in Sub/W(t)/Co 20 Fe 60 B 20 (3 nm)/SiO 2 (2 nm) heterostructures with variable W thickness.We employed an all-optical time-resolved magneto-optical Kerr effect microscope for an unambiguous determination of SHA using the principle of modulation of Gilbert damping of the adjacent ferromagnetic layer by the spin-orbit torque from the W layer. A non-monotonic variation of SHA with W layer thickness (t) is observed with a maximum of about 0.4 at about t = 3 nm, followed by a sudden reduction to a very low value at t = 6 nm. This variation of SHA with W-thickness correlates well with the thickness dependent structural phase transition and resistivity variation of W above the spin diffusion length of W, while below this length the interfacial electronic effect at W/CoFeB influences the estimation of SHA.2

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“…2(a) displays the measured TR-MOKE data points measured at H ex ¼ 11 kOe for Pd(t Pd )/[Co/ Ni] 5 samples with various t Pd . All the curves exhibit a precession and damping relaxation behavior, which were tted by using the following equation, 7,25…”

Section: Methodsmentioning

confidence: 99%

Magnetic damping and perpendicular magnetic anisotropy in Pd-buffered [Co/Ni]₅ and [Ni/Co]₅ multilayers

Tang

Ren

et al. 2017

RSC Adv.

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Time-Domain Study of Magnetization Dynamics in Magnetic Thin Films and Micro- and Nanostructures

Cited by 48 publications

References 253 publications

All optical detection of picosecond spin-wave dynamics in 2D annular antidot lattice

All optical detection of picosecond spin-wave dynamics in 2D annular antidot lattice

All-optical detection of the spin Hall angle inW/CoFeB/SiO2heterostructures with varying thickness of the tungsten layer

Magnetic damping and perpendicular magnetic anisotropy in Pd-buffered [Co/Ni]₅ and [Ni/Co]₅ multilayers

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Time-Domain Study of Magnetization Dynamics in Magnetic Thin Films and Micro- and Nanostructures

Cited by 48 publications

References 253 publications

All optical detection of picosecond spin-wave dynamics in 2D annular antidot lattice

All optical detection of picosecond spin-wave dynamics in 2D annular antidot lattice

All-optical detection of the spin Hall angle inW/CoFeB/SiO2heterostructures with varying thickness of the tungsten layer

Magnetic damping and perpendicular magnetic anisotropy in Pd-buffered [Co/Ni]5 and [Ni/Co]5 multilayers

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Magnetic damping and perpendicular magnetic anisotropy in Pd-buffered [Co/Ni]₅ and [Ni/Co]₅ multilayers