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Hanadi Mortada

Publications and source records attributed to Hanadi Mortada.

2 recordsLinked to original sources

Spin-wave phase modulation using magnetic domain walls in dipolarly coupled structures for non-volatile magnonic computation

A controllable phase shifter is a key component for spin-wave-based logic and information processing devices. Here, we propose a domain-wall-position-controlled spin-wave phase shifter that exploits dipolar coupling between two closely spaced waveguides to enable continuous phase tuning over a range approaching 360degrees while keeping the spin-wave amplitude constant. Using micromagnetic simulations, we model a bias-free hybrid structure composed of a nanoscale waveguide magnetostatically coupled to a half-ring-shaped structure both made from bismuth-doped yttrium iron garnet with strong perpendicular magnetic anisotropy. Displacing a domain wall in the half-ring modulates the dispersion relation in the adjacent straight waveguide due to the changed magnetostatic interaction, providing a compact and dynamically reconfigurable phase-shifting mechanism. This approach offers precise and non-volatile control over spin-wave propagation and is compatible with energy-efficient magnonic logic architectures.

cond-mat.mes-hall

An all-magnonic neuron with tunable fading memory

Magnonics offers nanometer-scale wave propagation and strong nonlinearities, making it attractive for neuromorphic applications such as artificial neurons. Yet, magnonic elements with interconnections solely within the magnonic system remain challenging, preventing the realization of interconnected magnonic neurons to date. Here, we experimentally demonstrate an all-magnonic neuron that reacts to magnon inputs with thresholded, amplified magnon firing and subsequent self-reset, enabling all-magnonic operation and cascading. Our approach is based on micro-antenna excitation on an ultra-low damping garnet with perpendicular magnetic anisotropy (PMA), where we exploit the positive magnon frequency shift to realize nonlinear activation. Using Brillouin light scattering spectroscopy, we uncover a transient neuron response with tunable fading memory: A 25% change in pump power results in a 3-order-of-magnitude tuning in memory time, which we harness, demonstrating temporal integration of up to 50 magnon pulses. Finally, we realize neuron triggering in a cascade of 3 neurons, highlighting its potential for connected magnonic circuits.

cond-mat.mtrl-sci