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Mechanism And Size Effects Of Helicity Dependent All Optical Magnetization Switching In Ferromagnetic Thin Films
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Book Synopsis Mechanism and Size Effects of Helicity-dependent All-optical Magnetization Switching in Ferromagnetic Thin Films by : Yassine Quessab
Download or read book Mechanism and Size Effects of Helicity-dependent All-optical Magnetization Switching in Ferromagnetic Thin Films written by Yassine Quessab and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pour des applications technologiques d'enregistrement magnétique de l'information à haute densité et vitesse d'écriture et de lecture ultra-rapide, les chercheurs se sont penchés vers des méthodes de manipulation de l'aimantation sans application de champ magnétique externe. Il a été découvert qu'il était possible de renverser de manière déterministe l'aimantation de plusieurs matériaux ferri- et ferro-magnétiques à l'aide uniquement d'impulsions laser ultracourtes polarisées circulairement. Ce retournement tout-optique s'est avéré être un processus cumulatif nécessitant plusieurs impulsions ultracourtes dans les matériaux ferromagnétiques. Notamment dans les multicouches (Co/Pt), le retournement tout-optique se fait en deux étapes : une désaimantation indépendamment de l'hélicité suivie d'une ré-aimantation dans une direction ou l'autre selon l'hélicité. Pour autant, le mécanisme à l'origine du rétablissement de l'ordre magnétique n'a pas été étudié jusqu'à présent. Dans cette thèse, nous avons étudié le mécanisme de renversement de l'aimantation dans les couches ferromagnétiques résultant de l'excitation par impulsions laser ultracourtes polarisées circulairement. Pour cela, nous étions intéressé par la réponse d'une paroi de domaine dans les couches minces de Pt/Co/Pt à la suite d'une excitation laser et en fonction de la polarisation de la lumière. Nous avons démontré la possibilité d'induire un déplacement tout-optique et déterministe d'une paroi de domaine. Nous montrons que la propagation de la paroi résulte de la compétition entre trois contributions : le gradient de température dû aux effets de chauffage par le laser, l'effet de l'hélicité de la lumière et les effets de piégeages de la paroi. Par ailleurs, par mesures expérimentales du dichroïsme circulaire, nous excluons un mécanisme purement thermique du déplacement de paroi. Ainsi nous confirmons que le retournement tout-optique des couches ferromagnétiques se fait par une nucléation suivie d'une ré-aimantation par propagation déterministe des parois de domaines selon l'hélicité. De plus, nous avons exploré la possibilité d'utiliser le retournement tout-optique dans des dispositifs spintroniques pour l'enregistrement de l'information à haute densité. Pour se faire, il est nécessaire d'étudier les effets de tailles du retournement lorsque le matériau est structuré en îlots à l'échelle du micro- ou nanomètre. Nous avons montré qu'un plus grand nombre d'impulsions laser est nécessaire afin de renverser l'aimantation de micro-disques comparés à la couche continue ferromagnétique. Il en résulte que le champ dipolaire aide le renversement de l'aimantation dans les couches continues rendant ainsi le retournement tout-optique énergétiquement plus favorable.
Book Synopsis Helicity-dependent All-optical Switching in Hybrid Metal-ferromagnet Structures for Ultrafast Magnetic Data Storage by : Feng Cheng
Download or read book Helicity-dependent All-optical Switching in Hybrid Metal-ferromagnet Structures for Ultrafast Magnetic Data Storage written by Feng Cheng and published by . This book was released on 2016 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emerging Big Data era demands the rapidly increasing need for speed and capacity of storing and processing information. Standalone magnetic recording devices, such as hard disk drives (HDDs), have always been playing a central role in modern data storage and continuously advancing. Recognizing the growing capacity gap between the demand and production, industry has pushed the bit areal density in HDDs to 900 Giga-bit/square-inch, a remarkable 450-million-fold increase since the invention of the first hard disk drive in 1956. However, the further development of HDD capacity is facing a pressing challenge, the so-called superparamagnetic effect, that leads to the loss of information when a single bit becomes too small to preserve the magnetization[1, 2]. This requires new magnetic recording technologies that can write more stable magnetic bits into hard magnetic materials. Recent research has shown that it is possible to use ultrafast laser pulses to switch the magnetization in certain types of magnetic thin films. Surprisingly, such a process does not require an externally applied magnetic field that always exists in conventional HDDs. Furthermore, the optically induced magnetization switching is extremely fast, up to sub-picosecond (10−12 s) level, while with traditional recording method the deterministic switching does not take place shorter than 20 ps [3]. It's worth noting that the direction of magnetization is related to the helicity of the incident laser pulses. Namely, the right-handed polarized laser pulses will generate magnetization pointing in one direction while left-handed polarized laser pulses generate magnetization pointing in the other direction. This so-called helicity-dependent all-optical switching (HD-AOS) phenomenon can be potentially used in the next-generation of magnetic storage systems. In this thesis, I explore the HD-AOS phenomenon in hybrid metal-ferromagnet structures, which consist of gold and Co/Pt multilayers. The experiment results show that such CoPtAu hybrid structures have stable HD-AOS phenomenon over a wild range of repetition rates and peak powers. A macroscopic three-temperature model is developed to explain the experiment results. In order to reduce the magnetic bit size and power consumption to transform future magnetic data storage techniques, I further propose plasmonic-enhanced all-optical switching (PE-AOS) by utilizing the unique properties of the tight field confinement and strong local field enhancement that arise from the excitation of surface plasmons supported by judiciously designed metallic nanostructures. The preliminary results on PE-AOS are presented. Finally, I provide a discussion on the future work to explore the underline mechanism of the HD-AOS phenomenon in hybrid metal-ferromagnetic thin films. Different materials and plasmonic nanostructures are also proposed as further work.
Book Synopsis All-Optical Helicity Dependent Switching Effect in Magnetic Thin Films by : Charles-Henri Lambert
Download or read book All-Optical Helicity Dependent Switching Effect in Magnetic Thin Films written by Charles-Henri Lambert and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The possibilities of modifying magnetization without applied magnetic fields have attracted growing attention over the past fifteen years. The low-power manipulation of magnetization, preferably at ultrashort timescales, has become a fundamental challenge with implications for future magnetic information memory and storage technologies. In particular the interplay of laser and magnetism recently discovered by Stanciu et al. opens up new way for light to be used as an excitation and a probe of magnetic materials. A description of the current models and frameworks developed in the field requires a careful look at the different parameters involved through the interaction of ultrafast lasers and magnetic materials. The specific and complex interplay between heat and angular momentum transfer is highlighted in order to discuss the role of each of them in the phenomena observed. The timescales of the different interactions responsible for the final state of magnetization are presented and will impact the way the system recovery after a laser excitation. Besides we were interested in exploring the relation between the material parameters such as anisotropy, ordering temperature and exchange coupling on the final state of magnetization obtained with a laser. Indeed thanks to the many different magnetism classes existing the magnetic parameters can be tuned widely and in a controlled manner. Our imaging setup then is able to probe the optical characteristics and domain stability after the laser excitation. We finally demonstrated that all-optical helicity-dependent switching (AO-HDS) can be observed not only in selected rare earth-transition metal (RE-TM) alloy films but also in a much broader variety of materials, including RE-TM alloys, multilayers and heterostructures. We further show that RE-free Co-Ir-based synthetic ferrimagnetic heterostructures designed to mimic the magnetic properties of RE-TM alloys also exhibit AO-HDS. We further developed the optical control of ferromagnetic materials ranging from magnetic thin films to multilayers and even granular films being explored for ultra-high-density magnetic recording. Our finding shows that optical control of magnetic materials is a much more general phenomenon than previously assumed and may have a major impact on data memory and storage industries through the integration of optical control of ferromagnetic bits.
Book Synopsis Handbook of Magnetism and Magnetic Materials by : Michael Coey
Download or read book Handbook of Magnetism and Magnetic Materials written by Michael Coey and published by Springer. This book was released on 2021-11-19 with total page 1679 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook presents a comprehensive survey of magnetism and magnetic materials. The dramatic advances in information technology and electromagnetic engineering make it necessary to systematically review the approved key knowledge and summarize the state of the art in this vast field within one seminal reference work. The book thus delivers up-to-date and well-structured information on a wealth of topics encompassing all fundamental aspects of the underlying physics and materials science, as well as advanced experimental methodology and applications. It features coverage of the host of fascinating and complex phenomena that arise from the use of magnetic fields in e.g. chemistry and biology. Edited by two internationally renowned scholars and featuring authored chapters from leading experts in the field, Springer’s Handbook of Magnetism and Magnetic Materials is an invaluable source of essential reference information for a broad audience of students, researchers, and magnetism professionals.
Book Synopsis Spin Dynamics and Damping in Ferromagnetic Thin Films and Nanostructures by : Anjan Barman
Download or read book Spin Dynamics and Damping in Ferromagnetic Thin Films and Nanostructures written by Anjan Barman and published by Springer. This book was released on 2017-12-27 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive overview of the latest developments in the field of spin dynamics and magnetic damping. It discusses the various ways to tune damping, specifically, dynamic and static control in a ferromagnetic layer/heavy metal layer. In addition, it addresses all optical detection techniques for the investigation of modulation of damping, for example, the time-resolved magneto-optical Kerr effect technique.
Book Synopsis Novel Magnetic Nanostructures by : Natalia Domracheva
Download or read book Novel Magnetic Nanostructures written by Natalia Domracheva and published by Elsevier. This book was released on 2018-06-14 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Novel Magnetic Nanostructures: Unique Properties and Applications reviews the synthesis, design, characterization and unique properties of emerging nanostructured magnetic materials. It discusses the most promising and relevant applications, including data storage, spintronics and biomedical applications. Properties investigated include electronic, self-assembling, multifunctional, and magnetic properties, along with magnetic phenomena. Structures range from magnetic nanoclusters, nanoparticles, and nanowires, to multilayers and self-assembling nanosystems. This book provides a better understanding of the static and dynamic magnetism in new nanostructures for important applications. Provides an overview of the latest research on novel magnetic nanostructures, including molecular nanomagnets, metallacrown magnetic nanostructures, magnetic dendrimers, self-assembling magnetic structures, multifunctional nanostructures, and much more Reviews the synthesis, design, characterization and detection of useful properties in new magnetic nanostructures Highlights the most relevant applications, including spintronic, data storage and biomedical applications
Author :Stefan Alexander Maier Publisher :Springer Science & Business Media ISBN 13 :0387378251 Total Pages :234 pages Book Rating :4.3/5 (873 download)
Book Synopsis Plasmonics: Fundamentals and Applications by : Stefan Alexander Maier
Download or read book Plasmonics: Fundamentals and Applications written by Stefan Alexander Maier and published by Springer Science & Business Media. This book was released on 2007-05-16 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: Considered a major field of photonics, plasmonics offers the potential to confine and guide light below the diffraction limit and promises a new generation of highly miniaturized photonic devices. This book combines a comprehensive introduction with an extensive overview of the current state of the art. Coverage includes plasmon waveguides, cavities for field-enhancement, nonlinear processes and the emerging field of active plasmonics studying interactions of surface plasmons with active media.
Book Synopsis The Physics of Ultra-High-Density Magnetic Recording by : M.L. Plumer
Download or read book The Physics of Ultra-High-Density Magnetic Recording written by M.L. Plumer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Application-oriented book on magnetic recording, focussing on the underlying physical mechanisms that play crucial roles in medium and transducer development for high areal density disk drives.
Book Synopsis Magnetic Oxides by : Gerald F. Dionne
Download or read book Magnetic Oxides written by Gerald F. Dionne and published by Springer Science & Business Media. This book was released on 2010-03-26 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic Oxides offers a cohesive up-to-date introduction to magnetism in oxides. Emphasizing the physics and chemistry of local molecular interactions essential to the magnetic design of small structures and thin films, this volume provides a detailed view of the building blocks for new magnetic oxide materials already advancing research and development of nano-scale technologies. Clearly written in a well-organized structure, readers will find a detailed description of the properties of magnetic oxides through the prism of local interactions as an alternative to collective electron concepts that are more applicable to metals and semiconductors. Researchers will find Magnetic Oxides a valuable reference.
Book Synopsis Handbook of Spintronics by : Yongbing Xu
Download or read book Handbook of Spintronics written by Yongbing Xu and published by Springer. This book was released on 2015-10-14 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over two volumes and 1500 pages, the Handbook of Spintronics will cover all aspects of spintronics science and technology, including fundamental physics, materials properties and processing, established and emerging device technology and applications. Comprising 60 chapters from a large international team of leading researchers across academia and industry, the Handbook provides readers with an up-to-date and comprehensive review of this dynamic field of research. The opening chapters focus on the fundamental physical principles of spintronics in metals and semiconductors, including an introduction to spin quantum computing. Materials systems are then considered, with sections on metallic thin films and multilayers, magnetic tunnelling structures, hybrids, magnetic semiconductors and molecular spintronic materials. A separate section reviews the various characterisation methods appropriate to spintronics materials, including STM, spin-polarised photoemission, x-ray diffraction techniques and spin-polarised SEM. The third part of the Handbook contains chapters on the state of the art in device technology and applications, including spin valves, GMR and MTJ devices, MRAM technology, spin transistors and spin logic devices, spin torque devices, spin pumping and spin dynamics and other topics such as spin caloritronics. Each chapter considers the challenges faced by researchers in that area and contains some indications of the direction that future work in the field is likely to take. This reference work will be an essential and long-standing resource for the spintronics community.
Book Synopsis Magnetic Heterostructures by : H. Zabel
Download or read book Magnetic Heterostructures written by H. Zabel and published by Springer. This book was released on 2007-10-26 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heterostructures consist of combinations of different materials, which are in contact through at least one interface. Magnetic heterostructures combine different physical properties which do not exist in nature. This book provides the first comprehensive overview of an exciting and fast developing field of research, which has already resulted in numerous applications and is the basis for future spintronic devices.
Book Synopsis The Physical Principles of Magneto-optical Recording by : Masud Mansuripur
Download or read book The Physical Principles of Magneto-optical Recording written by Masud Mansuripur and published by Cambridge University Press. This book was released on 1998-07-30 with total page 780 pages. Available in PDF, EPUB and Kindle. Book excerpt: First-time paperback of successful and well-reviewed book; for graduate students and researchers in physics and engineering.
Book Synopsis Electronic Structure of Disordered Alloys, Surfaces and Interfaces by : Ilja Turek
Download or read book Electronic Structure of Disordered Alloys, Surfaces and Interfaces written by Ilja Turek and published by Springer Science & Business Media. This book was released on 2013-11-27 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: At present, there is an increasing interest in the prediction of properties of classical and new materials such as substitutional alloys, their surfaces, and metallic or semiconductor multilayers. A detailed understanding based on a thus of the utmost importance for fu microscopic, parameter-free approach is ture developments in solid state physics and materials science. The interrela tion between electronic and structural properties at surfaces plays a key role for a microscopic understanding of phenomena as diverse as catalysis, corrosion, chemisorption and crystal growth. Remarkable progress has been made in the past 10-15 years in the understand ing of behavior of ideal crystals and their surfaces by relating their properties to the underlying electronic structure as determined from the first principles. Similar studies of complex systems like imperfect surfaces, interfaces, and mul tilayered structures seem to be accessible by now. Conventional band-structure methods, however, are of limited use because they require an excessive number of atoms per elementary cell, and are not able to account fully for e.g. substitu tional disorder and the true semiinfinite geometry of surfaces. Such problems can be solved more appropriately by Green function techniques and multiple scattering formalism.
Book Synopsis Ultrafast Magnetization Dynamics by : Simon Woodford
Download or read book Ultrafast Magnetization Dynamics written by Simon Woodford and published by Forschungszentrum Jülich. This book was released on 2008 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Handbook of Magnetic Materials by : Ekkes H. Brück
Download or read book Handbook of Magnetic Materials written by Ekkes H. Brück and published by Elsevier. This book was released on 2020-11-29 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handbook of Magnetic Materials, Volume 29, highlights new advances in the field, with this new volume presenting interesting chapters written by an international board of authors on topics such as spin-orbit torque. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in the Handbook of Magnetic Materials series
Download or read book Spin Current written by Sadamichi Maekawa and published by Oxford University Press. This book was released on 2017 with total page 541 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a new branch of physics and technology, called spin-electronics or spintronics, the flow of electrical charge (usual current) as well as the flow of electron spin, the so-called "spin current", are manipulated and controlled together. This book is intended to provide an introduction and guide to the new physics and applications of spin current.
Download or read book Atom Chips written by Jakob Reichel and published by John Wiley & Sons. This book was released on 2011-08-24 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: This stimulating discussion of a rapidly developing field is divided into two parts. The first features tutorials in textbook style providing self-contained introductions to the various areas relevant to atom chip research. Part II contains research reviews that provide an integrated account of the current state in an active area of research where atom chips are employed, and explore possible routes of future progress. Depending on the subject, the length of the review and the relative weight of the 'review' and 'outlook' parts vary, since the authors include their own personal view and style in their accounts.
