Spintronic and Electronic Oscillators for Magnetic Field Sensing and Ising Machines
Author: Dagur Ingi Albertsson
Publisher:
Published: 2023
Total Pages: 0
ISBN-13: 9789180405928
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MACROSPIN & MICROMAGNETIC SIMU
Author: Tui Zeng
Publisher: Open Dissertation Press
Published: 2017-01-26
Total Pages: 146
ISBN-13: 9781361014196
DOWNLOAD EBOOKThis dissertation, "Macrospin and Micromagnetic Simulations of Spintronic Devices for Magnetic Sensors and Oscillator Applications" by Tui, Zeng, 曾推, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: In this thesis, by categorizing the application of spintronic devices with the standard of signal type being processed, the spintronic devices based magnetic field sensors which process the D.C. signal are studied with micromagnetic simulation and the spintronic devices based spin-torque oscillators which process the A.C. signal are studied with macrospin simulation. By conducting micromagnetic simulation, the thermally excited mag-noise in spintronic device based magnetic field sensors is systematically studied. In magnetic tunnel junctions (MTJ) based magnetic field sensor, the spatial distribution of the thermally excited mag-noise indicates that the edges are the main contributor of thermal mag-noise in the free layer (FL). Both hard bias (HB) field and applied field could suppress the thermal mag-noise in edges. A relatively high applied field will decrease the influence of HB field on mag-noise in edges. The edge effect is not applicable for MTJ sensors with circular cross section. In ferromagnetic ring structure based magnetic field sensor, the saturated state, triangle state, half triangle state, onion state, and vortex state are explored and studied, respectively. The mag-noise calculation shows that triangle state is the main reason for the mag-noise exhibiting 1/f tendency in both the low-frequency range and high-frequency range in relaxed state, while the onion state explains why a noise peak appears in high-frequency range in the relaxed state. It is proved that the area of the ferromagnetic rings is not the determining factor for the thermal mag-noise distribution in the saturated state. In dual-vortex structure based magnetic field sensor, the combination of the dual-vortex motion and the magnetic noise properties make it possible to measure the external field (along hard bias direction) through measuring the FMR peak positions or the integrated thermal mag-noise, which indicated two novel field sensing mechanisms using elliptical permalloy single layer. Besides the study of the thermally excited mag-noise in spintronic device based magnetic field sensors, the spintronic device based spintorque oscillators (STOs) is fully investigated by macrospin simulation. Conclusions demonstrate numerically and analytically how a STO locks to a microwave field (Hac). A magnetic energy based analysis is used to explain this phenomenon. This result provides a possible way to synchronize serially connected STOs by tuning each single STO's phase shift with external microwave field, which could finally enhance the locking efficiency, locking range and output power of serially connected STOs. Meanwhile, the capacitance effect on the oscillation characteristics and the switching characteristics of the STOs has also been studied. The micromagnetic simulation of the noise sources in traditional GMR/TMR based magnetic field sensor and novel spintronic device based magnetic field sensors not onlyprovide reliable explanations of noise-related phenomenon in magnetic field sensors but also offer guidance on how to fabricate magnetic field sensors with relative low thermal magnetic noise and high performance. Meanwhile, the macrospin study of the spin-torque oscillators which process A.C electrical current signal has provided theoretical fundamentals for next generation microwave generator. Subjects: Spintronics - Materials Magnetic materials
Spin Electronics
Author: David D. Awschalom
Publisher: Springer Science & Business Media
Published: 2013-06-29
Total Pages: 216
ISBN-13: 9401705321
DOWNLOAD EBOOKThe history of scientific research and technological development is replete with examples of breakthroughs that have advanced the frontiers of knowledge, but seldom does it record events that constitute paradigm shifts in broad areas of intellectual pursuit. One notable exception, however, is that of spin electronics (also called spintronics, magnetoelectronics or magnetronics), wherein information is carried by electron spin in addition to, or in place of, electron charge. It is now well established in scientific and engineering communities that Moore's Law, having been an excellent predictor of integrated circuit density and computer performance since the 1970s, now faces great challenges as the scale of electronic devices has been reduced to the level where quantum effects become significant factors in device operation. Electron spin is one such effect that offers the opportunity to continue the gains predicted by Moore's Law, by taking advantage of the confluence of magnetics and semiconductor electronics in the newly emerging discipline of spin electronics. From a fundamental viewpoine, spin-polarization transport in a material occurs when there is an imbalance of spin populations at the Fermi energy. In ferromagnetic metals this imbalance results from a shift in the energy states available to spin-up and spin-down electrons. In practical applications, a ferromagnetic metal may be used as a source of spin-polarized electronics to be injected into a semiconductor, a superconductor or a normal metal, or to tunnel through an insulating barrier.
Electrical Transport in Nanoscale Systems
Author: Massimiliano Di Ventra
Publisher: Cambridge University Press
Published: 2008-08-07
Total Pages: 477
ISBN-13: 1139475029
DOWNLOAD EBOOKIn recent years there has been a huge increase in the research and development of nanoscale science and technology. Central to the understanding of the properties of nanoscale structures is the modeling of electronic conduction through these systems. This graduate textbook provides an in-depth description of the transport phenomena relevant to systems of nanoscale dimensions. In this textbook the different theoretical approaches are critically discussed, with emphasis on their basic assumptions and approximations. The book also covers information content in the measurement of currents, the role of initial conditions in establishing a steady state, and the modern use of density-functional theory. Topics are introduced by simple physical arguments, with particular attention to the non-equilibrium statistical nature of electrical conduction, and followed by a detailed formal derivation. This textbook is ideal for graduate students in physics, chemistry, and electrical engineering.
Introduction to Nanoscale Science and Technology
Author: Massimiliano Ventra
Publisher: Springer Science & Business Media
Published: 2006-04-11
Total Pages: 608
ISBN-13: 1402077572
DOWNLOAD EBOOKFrom the reviews: "...A class in nanoscale science and technology is daunting for the educator, who must organize a large collection of materials to cover the field, and for the student, who must absorb all the new concepts. This textbook is an excellent resource that allows students from any engineering background to quickly understand the foundations and exciting advances of the field. The example problems with answers and the long list of references in each chapter are a big plus for course tutors. The book is organized into seven sections. The first, nanoscale fabrication and characterization, covers nanolithography, self-assembly, and scanning probe microscopy. Of these, we enjoyed the section on nanolithography most, as it includes many interesting details from industrial manufacturing processes. The chapter on self-assembly also provides an excellent overview by introducing six types of intermolecular interactions and the ways these can be employed to fabricate nanostructures. The second section covers nanomaterials and nanostructures. Out of its 110 pages, 45 are devoted to carbon nanotubes. Fullerenes and quantum dots each have their own chapter that focuses on the properties and applications of these nanostructures. Nanolayer, nanowire, and nanoparticle composites of metals and semiconductors are briefly covered (just 12 pages), with slightly more discussion of specific applications. The section on nanoscale electronics begins with a history of microelectronics before discussing the difficulties in shrinking transistor size further. The discussion of problems (leakage current, hot electrons, doping fluctuations, etc.) and possible solutions (high- k dielectrics, double-gate devices) could easily motivate deeper discussions of nanoscale electrical transport. A chapter on molecular electronics considers transport through alkanes, molecular transistors, and DNA in a simple, qualitative manner we found highly instructive. Nanoscale magnetic systems are examined in the fourth section. The concept of quantum computation is nicely presented, although the discussion of how this can be achieved with controlled spin states is (perhaps necessarily) not clear. We found the chapter on magnetic storage to be one of the most lucid in the book. The giant magnetoresistive effect, operation of spin valves, and issues in magnetic scaling are easier to understand when placed in the context of the modern magnetic hard disk drive. Micro- and nanoelectromechanical systems are covered with an emphasis on the integration of sensing, computation, and communication. Here, the student can see advanced applications of lithography. The sixth section, nanoscale optoelectronics, describes quantum dots, organic optoelectronics, and photonic crystals. The chapter on organic optoelectronics is especially clear in its discussion of the fundamentals of this complicated field. The book concludes with an overview of nanobiotechnology that covers biomimetics, biomolecular motors, and nanofluidics. Because so many authors have contributed to this textbook, it suffers a bit from repetition. However, this also allows sections to be omitted without any adverse effect on student comprehension. We would have liked to see more technology to balance the science; apart from the chapters on lithography and magnetic storage, little more than an acknowledgment is given to commercial applications. Overall, this book serves as an excellent starting point for the study of nanoscale science and technology, and we recommend it to anyone with a modest scientific background. It is also a great vehicle to motivate the study of science at a time when interest is waning. Nanotechnology educators should look no further." (MATERIALS TODAY, June 2005)
The Scientific Method
Author: Massimiliano Di Ventra
Publisher: Oxford University Press
Published: 2018-07-19
Total Pages: 129
ISBN-13: 019255963X
DOWNLOAD EBOOKThis book looks at how science investigates the natural world around us. It is an examination of the scientific method, the foundation of science, and basis on which our scientific knowledge is built on. Written in a clear, concise, and colloquial style, the book addresses all concepts pertaining to the scientific method. It includes discussions on objective reality, hypotheses and theory, and the fundamental and inalienable role of experimental evidence in scientific knowledge. This collection of personal reflections on the scientific methodology shows the observations and daily uses of an experienced practitioner. Massimiliano Di Ventra also examines the limits of science and the errors we make when abusing its method in contexts that are not scientific, for example, in policymaking. By reflecting on the general method, the reader can critically sort through other types of scientific claims, and judge their ability to apply it in study and in practice.
Chaotic, Fractional, and Complex Dynamics: New Insights and Perspectives
Author: Mark Edelman
Publisher: Springer
Published: 2017-11-17
Total Pages: 320
ISBN-13: 3319681095
DOWNLOAD EBOOKThe book presents nonlinear, chaotic and fractional dynamics, complex systems and networks, together with cutting-edge research on related topics. The fifteen chapters – written by leading scientists working in the areas of nonlinear, chaotic, and fractional dynamics, as well as complex systems and networks – offer an extensive overview of cutting-edge research on a range of topics, including fundamental and applied research. These include but are not limited to, aspects of synchronization in complex dynamical systems, universality features in systems with specific fractional dynamics, and chaotic scattering. As such, the book provides an excellent and timely snapshot of the current state of research, blending the insights and experiences of many prominent researchers.
Solid State PhysicsMetastable, Spintronics Materials and Mechanics of Deformable Bodies
Author: Subbarayan Sivasankaran
Publisher: BoD – Books on Demand
Published: 2020-05-27
Total Pages: 238
ISBN-13: 1838811648
DOWNLOAD EBOOKThis book describes the recent evolution of solid-state physics, which is primarily dedicated to examining the behavior of solids at the atomic scale. It also presents various state-of-the-art reviews and original contributions related to solid-state sciences. The book consists of four sections, namely, solid-state behavior, metastable materials, spintronics materials, and mechanics of deformable bodies. The authors’ contributions relating to solid-state behavior deal with the performance of solid matters pertaining to quantum mechanics, physical metallurgy, and crystallography. The authors’ contributions relating to metastable materials demonstrate the behavior of amorphous/bulk metallic glasses and some nonequilibrium materials. The authors’ contributions relating to spintronic materials explain the principles and equations underlying the physics, transport, and dynamics of spin in solid-state systems. The authors’ contributions relating to the mechanics of deformable bodies deal with applications of numeric and analytic solutions/models for solid-state structures under deformation. Key Features:Issues in solid-state physics, Lagrangian quantum mechanics,Quantum and thermal behavior of HCP crystals,Thermoelectric properties of semiconductors,Bulk metallic glasses and metastable atomic density determination,Applications of spintronics and Heusler alloys, 2D elastostatic, mathematical modeling and dynamic stiffness methods on deformable bodies.
Trends in Magnetism
Author: V. Ustinov
Publisher: Trans Tech Publications Ltd
Published: 2010-12-30
Total Pages: 584
ISBN-13: 3038135089
DOWNLOAD EBOOKThe purpose of this special collection of peer-reviewed papers was to provide an opportunity for scientists from all over the world to share details of recent advances in the physics of magnetic materials. Volume is indexed by Thomson Reuters CPCI-S (WoS). The work is divided into: I. To the Memory of S.V.Vonsovsky, II. Spin-Polarized Transport, III. Spin Dynamics, Spin Waves, Spin-Wave Resonance, IV. Spin Reorientation Phase Transitions, V. Spin-Orbit and Exchange Interactions, Magnetic Anisotropy and Magnetostriction, VI. Dynamics of Domain Structures and Domain Walls, VII. Magnetic Nanostructures and Films, VIII. Magnetism and Nanomaterials, IX. Low-Dimensional Magnetism, X. Magnetism of Strongly Correlated Systems, XI. Magnetotransport and Magneto-Optics.
Quantum Gases
Author: Nick Proukakis
Publisher: World Scientific
Published: 2013
Total Pages: 579
ISBN-13: 1848168128
DOWNLOAD EBOOKThis volume provides a broad overview of the principal theoretical techniques applied to non-equilibrium and finite temperature quantum gases. Covering Bose-Einstein condensates, degenerate Fermi gases, and the more recently realised exciton-polariton condensates, it fills a gap by linking between different methods with origins in condensed matter physics, quantum field theory, quantum optics, atomic physics, and statistical mechanics.
