Skyrmion-electronics: Writing, deleting, reading and processing magnetic skyrmions toward spintronic applications

Abstract: The field of magnetic skyrmions has been actively investigated across a wide range of topics during the last decades. In this topical review, we mainly review and discuss key results and findings in skyrmion research since the first experimental observation of magnetic skyrmions in 2009. We particularly focus on the theoretical, computational and experimental findings and advances that are directly relevant to the spintronic applications based on magnetic skyrmions, i.e. their writing, deleting, reading and processing driven by magnetic field, electric current and thermal energy. We then review several potential applications including information storage, logic computing gates and non-conventional devices such as neuromorphic computing devices. Finally, we discuss possible future research directions on magnetic skyrmions, which also cover rich topics on other topological textures such as antiskyrmions and bimerons in antiferromagnets and frustrated magnets.

• The paper presents a comprehensive survey categorizing techniques for writing and deleting skyrmions using magnetic fields, electric currents, and VCMA methods.
• It reviews experimental approaches like spin-polarized tunneling, Hall resistivity measurements, and advanced imaging for reliable skyrmion detection.
• Findings indicate that novel materials such as antiferromagnets and 2D magnets enhance skyrmion stability, supporting high-density, energy-efficient spintronic devices.

Overview of Skyrmion-Electronics: Writing, Deleting, Reading, and Processing Magnetic Skyrmions Toward Spintronic Applications

The paper "Skyrmion-Electronics: Writing, Deleting, Reading and Processing Magnetic Skyrmions Toward Spintronic Applications" presents a comprehensive survey of advances in the field of magnetic skyrmions, particularly focusing on their prospective applications in spintronics. Following the first experimental observation in 2009, magnetic skyrmions have garnered significant interest due to their quasi-particle nature and unique topological properties, which offer promising opportunities for data storage and processing technologies.

Key Contributions and Findings

The authors categorize the research into specific areas of skyrmion manipulation and application—writing, deleting, reading, and processing. These areas are integral to developing skyrmion-based devices such as racetrack memory, logic gates, and neuromorphic computing devices.

1. Writing and Deleting Skyrmions: Methods for the creation and annihilation of magnetic skyrmions are pivotal for information encoding in skyrmion-based memory devices. These methods include the application of magnetic and electric fields, electric currents, and laser irradiation. The manipulation typically exploits the internal magnetic interactions to stabilize skyrmions in desired states. The paper reviews the effectiveness of these approaches, referencing techniques such as spin-polarized tunneling currents and VCMA manipulations initiated by electric fields.
2. Reading Skyrmions: For device integration, reading mechanisms focus on detecting skyrmions, which involve techniques such as Hall resistivity measurements and advanced imaging methods like X-ray microscopy and Lorentz TEM. The electrical detection via topological Hall effect (THE) emerges from the emergent magnetic fields associated with skyrmions, presenting a pathway for efficient signal conversion.
3. Processing Skyrmions: Skyrmions provide a mechanism for processing information through their controlled dynamics, such as current-driven motion and Skyrmion Hall Effect. The authors discuss how these effects allow skyrmions to function in applications like racetrack memories and logic devices, and how their dynamics can be manipulated in nanostructures for enhanced functionalities.

Stable and Novel Skyrmion-hosting Materials

The paper also addresses the future potential of novel material systems such as antiferromagnets, synthetic antiferromagnets, ferrimagnets, frustrated magnets, and 2D van der Waals magnets. These materials offer different stabilization mechanisms for skyrmions, potentially leading to improved efficiency and scalability for future technological applications. Special attention is given to antiferromagnetic and ferrimagnetic systems, as they can offer advantages like reduced Skyrmion Hall Effect and enhanced data processing speeds.

Advances in Skyrmion Application

Apart from memory applications, skyrmions show promise in logic and neuromorphic computing. The skyrmion-based logic gates can perform fundamental operations, potentially integrating into computing systems that parallel neuromorphic architectures. The paper highlights applications ranging from microwave devices and oscillators to synaptic devices for neuromorphic systems.

Theoretical Implications and Future Pathways

The authors envisage that continued research will focus on more efficient skyrmion manipulation techniques, novel material applications, and refined device architectures that leverage the low-energy and high-density advantages skyrmions provide. Future studies may explore the fundamental physics that underpins skyrmion behavior under varied external conditions, fostering innovations in computational and storage technology sectors.

In conclusion, the surveyed advances underscore the viability of skyrmions in creating a new class of spintronic devices, bridging the gap between theoretical physics and practical technology development. With ongoing interdisciplinary efforts, the realization of skyrmion-based devices seems imminent, paving the way for transformative advancements in data-centric technologies.