Curvilinear Micromagnetism: From Fundamentals to Applications

Description

This is the first book providing overview of magnetism in curved geometries, highlighting numerous peculiarities emerging from geometrically curved magnetic objects such as curved wires, shells, as well as complex three-dimensional structures. Extending planar two-dimensional structures into the three-dimensional space has become a general trend in multiple disciplines across electronics, photonics, plasmonics and magnetics. This approach provides the means to modify conventional and even launch novel functionalities by tailoring the local curvature of an object. The book covers the theory of curvilinear micromagnetism as well as experimental studies of geometrically curved magnets including both fabrication and characterization. With its coverage of fundamental aspects, together with exploration of numerous applications across magnonics, bio-engineering, soft robotics and shapeable magnetoelectronics, this edited collection is ideal for all scientists in academia and industry seeking an overview and wishing to keep abreast of advances in the novel field of curvilinear micromagnetism. It provides easy but comprehensive access to the field for newcomers, and can be used for graduate-level courses on this subject. Preface References Contents Contributors 1 Geometry-Induced Magnetic Effects in Planar Curvilinear Nanosystems 1.1 Introduction 1.2 Model of Curved 1D Ferromagnetic Systems 1.3 Curvature-Induced Effects in Flat Magnetic Systems 1.3.1 Wire with a Constant Curvature—Ring–Shaped Wire 1.3.2 Wire with a Box–Function Curvature 1.3.3 Wire with Periodical Curvature Distribution 1.4 Domain Walls in Curved Ferromagnetic Wires 1.4.1 Statics of the Domain Wall 1.4.2 Dynamics of the Domain Wall 1.4.3 Domain Wall Depinning Experiments 1.5 Fabrication and Characterization 1.5.1 Lithographic Methods 1.5.2 Ion-Induced Methods 1.5.3 Magnetic Characterization 1.6 Conclusion and Outlook References 2 Effects of Curvature and Torsion on Magnetic Nanowires 2.1 Introduction 2.2 Geometry of Space Curves 2.3 Model of a Curvilinear Ferromagnetic Wire in 3D Space 2.3.1 Wires with a Circular Cross-Section 2.3.2 Narrow Ribbons 2.4 Implications 2.4.1 Ground States 2.4.2 Linear Dynamics 2.4.3 Curvilinear Wires for Spintronics and Spin-Orbitronics Applications 2.4.4 Artificial Magnetoelectric Materials 2.5 Curvilinear Antiferromagnetic Spin Chains 2.5.1 Micromagnetic Description of a Spin Chain 2.5.2 Geometry-Driven Biaxial Chiral Helimagnets 2.5.3 Interplay Between Anisotropy and Geometry 2.5.4 Geometry-Induced Weak Ferromagnetism 2.6 Experimental Studies 2.6.1 Fabrication 2.6.2 Characterization 2.7 Concluding Remarks and Outlook References 3 Curvilinear Magnetic Shells 3.1 Introduction 3.2 Fundamentals of Curvilinear Magnetism of Shells 3.2.1 Lexicon of Differential Geometry of Surfaces 3.2.2 Magnetic Energy of Curvilinear Shells 3.2.3 Emergent Interactions: Symmetry, Curvature and Textures 3.3 Curvature–Induced Effects 3.3.1 Topological Patterning 3.3.2 Geometrical Magnetochiral Effects 3.4 Manipulation of Topologically Protected Magnetic States in Curved Shells 3.4.1 Skyrmions in Curvilinear Shells Engineered by Mesoscale DMI 3.4.2 Magnetic Vortex on a Spherical Cap: Polarity-Circulation Coupling 3.4.3 Control of the Magnetochiral Effects by Magnetic Fields 3.4.4 Dynamics of Topological Textures in Curved Films 3.5 Experimental Platforms 3.5.1 Hollow Nanoshells: A New Playground for Curvilinear Magnetism 3.5.2 Nanosphere Lithography: A Versatile Tool for Manufacturing Spherically Shaped Magnetic Nanostructures 3.5.3 Ion–Induced Surface Nanopatterning: Bottom-Up Templates for Curvilinear Magnetic Shells 3.6 Conclusion and Outlook References 4 Tubular Geometries 4.1 Introduction 4.2 Statics Properties of Tubular Nanomagnets 4.2.1 Magnetic Configurations at Equilibrium 4.2.2 Fabrication of Magnetic Tubular Geometries 4.2.3 Magnetization Reversal Process 4.3 Dynamical Properties 4.3.1 Chiral Domain Wall Motion 4.3.2 Vortex Domain Wall Dynamics—General Remarks 4.4 Spin wave Propagation 4.4.1 Theory of Spin Waves in Magnetic Nanotubes 4.5 Summary and Outlook References 5 Complex-Shaped 3D Nanoarchitectures for Magnetism and Superconductivity 5.1 Theoretical Background 5.2 Methods of Fabrication of 3D Nanoarchitectures 5.3 3D Magnetic Nanoarchitectures Fabricated by Optical Writing 5.4 3D Magnetic Nanoarchitectures Fabricated by FEBID 5.4.1 Basics and 3D Writing Aspects of FEBID 5.4.2 3D Magnetic Wireframe Building Blocks 5.4.3 3D Magnetic Nanoarchitectures 5.4.4 Complex-Shaped 3D Nanoarchitectures for Plasmonics and Beyond 5.5 3D Nanoarchitectures for Superconductivity References 6 Imaging of Curved Magnetic Architectures 6.1 Introduction 6.2 Overview of Microscopy Approaches to Image Curved Magnetic Architectures 6.2.1 Magneto-Optical Microscopies 6.2.2 X-Ray Microscopies 6.2.3 Electron Microscopies 6.2.4 Neutron Microscopies 6.2.5 Scanning Probe Microscopies 6.3 Future Directions—Challenges and Opportunities References 7 Curvilinear Magnetic Architectures for Biomedical Engineering 7.1 General Overview of the Field: Magnetic Micro/Nanomotors 7.2 The Role of Asymmetry in the Generation of Motion 7.2.1 Scallop Theorem 7.2.2 Asymmetry of the Micro/Nanomotors 7.2.3 Symmetry Breaking to Get Deterministic Motion of the Micro-/Nanomotors 7.3 Major Applications for the Life Sciences and Environment 7.3.1 Environmental and Bio Remediation 7.3.2 Biosensing 7.3.3 Drug Delivery References 8 Magnetic Soft Actuators: Magnetic Soft Robots from Macro- to Nanoscale 8.1 Introduction 8.2 Mechanics of Magnetic Soft Robots 8.2.1 Mechanisms of Actuation 8.2.2 Relevant Torques 8.2.3 Range of Motion 8.2.4 Available Force 8.2.5 Available Work 8.3 Magnetostatic Energy of Thin Films 8.4 Magnetoelastic Systems at the Nanoscale 8.4.1 Nanoscale Flexible One-Dimensional Wires 8.4.2 Nanoscale Flexible Ribbons 8.5 Concluding Remarks References 9 Geometrically Curved Magnetic Field Sensors for Interactive Electronics 9.1 Introduction 9.2 Background 9.2.1 Interactive Devices, Human-Machine Interfaces, and Virtual Reality 9.2.2 Soft Human–Machine Interfaces and Magnetosensitive E-Skins 9.2.3 Flexible Electronics and E-Skins 9.3 Magnetosensitive E-Skins with Directional Perception 9.4 Geomagnetosensitive E-Skins 9.5 On-Site Conditioned Magnetosensitive E-Skins 9.6 Magnetosensitive E-Skins with Multimodal Capabilities 9.7 Magnetosensitive E-Skins with Intrinsic Logic and Out-of-Plane Detection 9.8 Magnetic Soft Actuators with Embedded Flexible E-Skin Sensing Modules 9.9 Summary 9.10 Outlook References Index