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A novel route for magnon transport: Spin-wave-based devices promise to usher in an era of low-power computing where information is carried by the precession of the electrons’ spin instead of dissipative translation of their charge. We have developed a new waveguide that eliminate the requirement of a stand-by power during operation. For the proof-of-concept device demonstration, the signal was measured using micro-focused Brillouin light scattering technique with a laser spot diameter of 250nm, which is the best-known tool for spatial imaging of spin waves. The devices were fabricated using state-of-art nanofabrication techniques. This recent work has been published in Nature Nanotechnology (Advance Online Publication: Feb 1, 2016). URL: http://dx.doi.org/10.1038/nnano.2015.332
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Large area artificial and anti-spin ice structures: In our recent publication in Adv. Func. Mater., the nanofabrication of large area artificial spin ice and anti-spin ice structures with magnetic elements arranged in three lattice configurations is reported using using deep ultraviolet lithography at 193 nm exposure wavelength. We demonstrate that the static and dynamic behaviors of these structures are highly tunable. http://pubs.acs.org/doi/abs/10.1021/acsnano.5b07849
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Complex spin wave modes in thick nanodots: In our recent publication (Phys. Rev. B 92, 054401, 2015), We have investigated the spin wave modes in perpendicularly magnetized Ni80Fe20 nanodots as a function of film thickness using field modulated perpendicular ferromagnetic resonance spectroscopy. As the thickness of the dot array increases, spin wave modes, with quantization along the axial and radial directions, are detected. In addition, axially antisymmetric standing spin wave mode as well as a circulating chiral mode near the dot surface have also been observed for thicker dots.
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Engineering spin dynamics: The magnetic exchange interactions (i.e. RKKY, dipolar coupling, exchange bias) affects the magnetic ground state in multilayer structures, with consequent influences in their magnetic properties. By a fine control over interlayers coupling, we have engineered the dynamics as well as static behaviours in lithographically patterned heterostructures at the nanoscale. Our results have practical applications in the optimization in magnonic crystals properties, and represent a iterating way to control their spin dynamics.
Spin wave autocollimation in planar magnonic crystals: We present a systematic study of spin wave autocollimation in planar magnonic crystals comprising of antidot arrays in nanoscale permalloy (Py: Ni80Fe20) thin films. It is shown that a careful design of such crystals can allow for the autocollimation of the entire spin wave spectrum without any significant evanescence or any drop in the group velocity. These developments allow us access to spin wave beams which do not disperse or converge outside a waveguide. Collimated spin wave beams would be essential in applications such as dense signal routing and multiplexing in higher dimensional magnonic systems. A new method for vortex chirality control: In a recent publication in Appl. Phys. Lett., we have proposed and experimentally demonstrated a new methodology for deterministic control of vortex chirality which might be useful for vortex based information processing. Control of chirality in tiny magnetic disks (diameter 700 nm) was obtained by using dipolar coupled rhomboid nanomagnets. -
Unusual opto-electrical response in metal-oxide-metal planar structures: We demonstrate unusual electrical behavior and large optoelectrical response in Pt-NiO-Pt planar structures, facilitated by electroformation. The simple design, robust and fast photoresponse, low dark current level and ease of preparation of these structures make them attractive for various photodetector and optoelectrical device applications. Our results are recently published in Scientific Reports, which may further broaden the range of applications of NiO and other metal-oxide junctions.
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