Kavli Affiliate: Darrell Schlom
| First 5 Authors: Arundhati Ghosal, Arundhati Ghosal, , ,
| Summary:
Conventional racetrack memories move information by pushing magnetic domain
walls or other spin textures with spin-polarized currents, but the accompanying
Joule heating inflates their energy budget and can hamper scaling. Here we
present a voltage-controlled, magnetoelectric racetrack in which transverse
electric fields translate coupled ferroelectric-antiferromagnetic walls along
BiFeO3 nanostrips at room temperature. Because no charge traverses the track,
the switching dissipates orders of magnitude less energy than the most
efficient spin-torque devices with more favourable scaling, making the scheme
significantly more attractive at the nanoscale. We further uncover noncollinear
topological magnetoelectric textures that emerge at domain walls in BiFeO3,
where the nature of these topologies influences their stability upon
translation. Among these are polar bi-merons and polar vertices
magnetoelectrically coupled with magnetic cycloid disclinations and previously
unobserved, topological magnetic cycloid twist topologies. We observe domain
wall velocities of at least kilometres per second – matching or surpassing the
fastest ferrimagnetic and antiferromagnetic racetracks and approaching the
acoustic-phonon limit of BiFeO3 – while preserving these topologies over tens
of micrometres. The resulting high velocity, low-energy racetrack delivers
nanosecond access times without the thermal overhead of current-driven schemes,
charting a path toward dense, ultralow-power racetrack devices which rely on
spin texture translation.
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