Scenarios and Principles for Antiferromagnetic Recording: taming spins coherently and ultrafast

Thermodynamics tells us that controlling the magnetic state of media at increasingly higher rates and simultaneously consuming less energy are mutually exclusive. This fundamental dilemma has dramatic societal and environmental consequences as data centres are rapidly becoming the biggest consumers of electricity world-wide.SPARTACUS proposes to resolve this fundamental dilemma and thereby to inspire conceptually new technology for ultrafast, nearly non-dissipative data storage.State-of-the-art data storage and non-volatile memory are predominantly based on ferromagnets. Antiferromagnets possess much faster spin dynamics and can sustain bits writing even at THz rates. However, the lack of a net magnetization in thermodynamic equilibrium requires exceedingly strong magnetic fields to control their magnetic moments. This fact has significantly hindered not only applications, but even fundamental studies of antiferromagnetism.SPARTACUS aims to overcome this fundamental problem and achieve nearly non-dissipative and fastest writing of bits at write-rewrite rates surpassing the 1 THz landmark. Using spectrally and temporally tailored laser pulses to pump electronic and phononic states mediating efficient light-spin coupling, we will push dielectric antiferromagnets strongly out-of-equilibrium, and explore the susceptibility of spins to external stimuli in this non-equilibrium state. SPARTACUS will develop novel ultrafast magnetometers and reveal yet unexplored non-thermodynamic routes to coherently steer spins to a desired bit state. Coherence-mediated ultrafast mechanisms ensure reversible energy transfer to overcome the potential barrier between stable bit states, minimizing the increase of entropy and leading to vanishing heat load.Although SPARTACUS is fundamental in nature, its long-term ambition is to shift the paradigm from the conventional, slow, energy consuming ferro- to ultrafast and nearly non-dissipative antiferromagnetic data storage.