Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - ASPIN (Antiferromagntic spintronics)

Teaser

Antiferromagnets and ferromagnets represent two fundamental forms of magnetism with antiferromagnets being the more abundant of the two. However, it has been notoriously difficult to manipulate and detect antiferromagnetic order by any practical means. The project builds on...

Summary

Antiferromagnets and ferromagnets represent two fundamental forms of magnetism with antiferromagnets being the more abundant of the two. However, it has been notoriously difficult to manipulate and detect antiferromagnetic order by any practical means. The project builds on our recent discoveries of new relativistic phenomena that allow us to efficiently control and detect antiferromagnetic moments in spintronic devices and by this to unlock a multitude of known and newly identified unique features of this class of materials. We are exploring three intertwined research areas in order to scientifically establish the following: (i) The concept of antiferromagnetic memories suitable for the development of future “Beyond Moore” information technologies. (ii) The concept of antiferromagnetic spintronic components operating at timescales as short as picoseconds. (iii) The concept in which antiferromagnets provide a unifying platform for realizing synergies between spintronics and topological phenomena. The project opens and explores a new research avenue, with emerging and future information technologies at its horizon, where antiferromagnets take the center stage. The era of the International Technology Roadmap for Semiconductors is now officially at an end. The project will introduce to the public sector and industry an entirely new technology concept of microelectronics based on antiferromagnets. It is foreseen to have an impact on future IoT technologies by breaking present limits on energy efficiency, speed, integration, and security.

Work performed

The research results obtained in the initial period of the project are summarized in the work package deliverables D1.1, D1.2, D2.1, and D3.1.

In the D1.1 report we summarize the work of the ASPIN project consortium aiming at predicting new and explaining existing experimental observations on writing, reading, processing, and storing information in antiferromagnetic spintronic devices. It spans a broad range of works from those directly relevant to our proof-of-concept digital and analogue antiferromagnetic memory cells to fundamental studies of spin-dependent transport, domain structure and dynamics in antiferromagnets. Apart from the reference to several of our comprehensive reviews, covering our as well as world-wide research in the field, the report outlines our original results in selected specific topics, namely: i) Antiferromagnetic memory devices, ii) spin transport in complex antiferromagnetic systems, iii) spintronics in insulating antiferromagnets, and iv) antiferromagnetic THz detector and emitter based on spin torques.

In the D1.2 report we summarize the work of the ASPIN project consortium on X-ray magnetic linear
dichroism measurements of Néel vector reorientations and domain reconfigurations in CuMnAs. The report outlines the following original results: i) Imaging current-induced switching of antiferromagnetic domains in CuMnAs, ii) current polarity-dependent manipulation of antiferromagnetic domains, and iii) control of antiferromagnetic spin axis orientation in bilayer Fe/CuMnAs films.

In the D2.1 report we summarize the work of the ASPIN project consortium on optical and THz detection and excitation of dynamics in antiferromagnets. It spans a broad range of works from developing the tools with high temporal and spatial resolution and studies of the fundamentals of spin-dynamics, to demonstrations of THz-pulse electrical switching of antiferromagnetic memory devices and THz spintronic emitters. Apart from the reference to our comprehensive review, covering our as well as world-wide research in the field, the report outlines our original results in selected specific topics, namely: i) Optical detection of antiferromagnetic moments in CuMnAs, ii) time-resolved optical detection of laser-pulse induced dynamics in insulating antiferromagnets, iii) magneto-optical microscope integrated in a pump-probe experimental setup, iv) writing by THz pulses in a CuMnAs antiferromagnetic memory, and v) THz spectroscopy, spin-currents, and spintronic emitters.

In the D3.1 report we summarize the work of the ASPIN project consortium on ab initio band structure calculations and symmetry/topology analyses in antiferromagnets. It spans a broad range of works from the study of the topological metal-insulator transition in Dirac semimetal antiferromagnets, to anomalous Hall effect in Weyl semimetal antiferromagnets. Apart from references to our comprehensive reviews, covering our as well as world-wide research in the field, the report outlines our original results in selected specific topics, namely: i) Dirac and Weyl band crossings in antiferromagnets, ii) Band structure of CuMnAs probed by ab initio calculations and optical and photo-emission spectroscopy.

Final results

\"Spintronics is considered among the potential paradigm changing technologies for the \"\"Beyond Moore\"\" era. Present spintronic technologies rely on ferromagnets, however, ferromagnets possess innate limitations in packing density, magnetic-field hardness and utility in memristive-like (synapse-like) devices due to dipolar stray fields. Moreover, their operation speed is limited by the GHz ferromagnetic resonance scale.

Independently, the discovery of graphene and topological phenomena opened another prominent avenue of research in the “Beyond Moore” technology domain. In physics, While fascinating theoretically, practical means for controlling topologoical phases in devices have remained elusive. Spintronics could be a key here, however, ferromagnets again offer only a limited playground constrained by symmetry.

These limitations can be lifted by including antiferromagnets into spintronics as already demonstrated by our initial results. However, our understanding of basic principles that might allow in the future for turning our new antiferromagnetic spintronics concept into applications is still at its infancy. A continuing fundamental research program is necessary for fully unraveling the physical, material, and device aspects that govern the write/read speed and efficiency, and the retention characteristics of antiferromagnetic digital and analogue memory cells. Among others this will require improving our toolbox of techniques for imaging antiferromagnetic domain structures and dynamics with high spatial and temporal resolution. In the end, if successful, ASPIN will not merely enable a future digital or neuromorphic, and ultra-fast memory technology based on antiferromagnets. It will impact the entire research field of antiferromagnets whose utility has, so far, remained a virtually unwritten chapter in magnetism.
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Website & more info

More info: http://www.aspin-project.eu/.