Study of Domain Wall Dynamics in the Presence of Large Spin Orbit Coupling

Study of Domain Wall Dynamics in the Presence of Large Spin Orbit Coupling
Author: Safeer Chenattukuzhiyil
Publisher:
Total Pages: 0
Release: 2015
Genre:
ISBN:

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Magnetic domain wall (DW) dynamics is currently attracting tremendous interest both from a fundamental point of view as well as in relation with emerging magnetic memory and logic devices. New DW-based devices were recently proposed, for example to replace hard drive disks with higher density and faster date transfer. Moreover, in Magnetic Random Access Memory (MRAM), identified as one of the most promising candidate for DRAM and SRAM replacement, switching occurs through DW propagation. Control of current induced DW dynamics has long been a challenge mainly due to material imperfections. Only some years ago, fast and controllable motions were reported in multilayers presenting structural inversion asymmetry (SIA). More recently, a mechanism was proposed based on the presence of spin orbit torques and Dzyaloshinskii-Moriya interaction (DMI), both phenomena originating from the spin orbit interaction and needing (SIA).My initial objective was to test this model in two systems presenting different SIA. In Pt/Co/Pt multilayers with weak SIA, I studied both current and field induced DW motion and evidenced a chiral damping. This new phenomena, counterpart of the DMI for the dissipative aspects, influences both current and field induced dynamics and has to be taken into account for a complete picture of the mechanism. In Pt/Co/AlOx multilayers with strong SIA, I studied new geometries where the DW motion the and current flow are not collinear. I evidenced asymmetric DW motion as a function of this non-collinearity that cannot be explained with a simple SOT+DMI model. Based on these experimental results I introduce a new device concept named “magnetic origami”: the shape of the device governs the switching mechanism. This concept provides large flexibility to construct fast, low power non-volatile magnetic memory: different functionalities can be achieved on a wafer by simply mastering the shape of the different elements. I show the proof of concept of two such devices.

Spin Dynamics in the Presence of Spin-orbit Interactions

Spin Dynamics in the Presence of Spin-orbit Interactions
Author: Xin Liu
Publisher:
Total Pages:
Release: 2012
Genre:
ISBN:

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We study the spin dynamics in a high-mobility two dimensional electron gas (2DEG) system with generic spin-orbit interactions (SOIs). We derive a set of spin dynamic equations which capture the purely exponential to the damped oscillatory spin evolution modes observed in different regimes of SOI strength. Hence we provide a full treatment of the D'yakonov-Perel's mechanism by using the microscopic linear response theory from the weak to the strong SOI limit. We show that the damped oscillatory modes appear when the electron scattering time is larger than half of the spin precession time due to the SOI, in agreement with recent observations. We propose a new way to measure the scattering time and the relative strength of Rashba and linear Dresselhaus SOIs based on these modes and optical grating experiments. We discuss the physical interpretation of each of these modes in the context of Rabi oscillation. In the finite temperature, We study the spin dynamics in the presence of impurity and electron-electron (e-e) scattering in a III-V semiconductor quantum well. Starting from the Keldysh formalism, we develop the spin-charge dynamic equation at finite temperature in the presence of inelastic scattering which provide a new approach to describe the spin relaxation from the weak to the strong spin-orbit coupling (SOC) regime. In the weak SOC regime, our theory shows that when the system is near the SU(2) symmetry point, because the spin relaxation due to DP mechanism is suppressed dramatically, the spin relaxation is dominated by the Elliott-Yafet (EY) mechanism in a wide temperature regime. The non-monotonic temperature dependence of enhanced-lifetime of spin helix mode is due to the competition between the DP and EY mechanisms. In the strong SOC regime, the our theory is consistent to the previous theoretical results at zero temperature.

Spin Dynamics and Damping in Ferromagnetic Thin Films and Nanostructures

Spin Dynamics and Damping in Ferromagnetic Thin Films and Nanostructures
Author: Anjan Barman
Publisher: Springer
Total Pages: 166
Release: 2017-12-27
Genre: Technology & Engineering
ISBN: 3319662961

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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.

Itinerant Spin Dynamics in Structures of Reduced Dimensionality

Itinerant Spin Dynamics in Structures of Reduced Dimensionality
Author: Paul Thomas Wenk
Publisher:
Total Pages: 161
Release: 2011
Genre:
ISBN:

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In the present thesis results of the study of spin dynamics and quantum transport in disordered semiconductor quantum wires with spin-orbit coupling are presented. Starting from basic spin dynamics we derive the dependence of the weak localization correction to the conductance on the strength and the kind of spin-orbit interaction (linear and cubic Dresselhaus, as well as Rashba coupling), the width of the quantum wires as well as the mobility, temperature and Zeeman term. Furthermore, we exploit the connection found between the microscopic picture given by the Cooperon and the spin diffusion equation to extract the spin relaxation rate which shows the same wire dependencies as the weak localization correction. We also show how the result depends on the smoothness and the direction of the transverse confinement of the quantum wires. In this context we have addressed the question concerning long persisting or even persistent spin states in spintronic devices, presenting the corresponding optimal adjustment of spin orbit couplings of different kind and optimal alignment of the wire direction in semiconductor crystals. Experiments\cite{Holleitner2006,Holleitner2007,Kunihashi2009a,Lehnen2007,hu05_4,Schapers2009} which report the dimensional reduction of the spin relaxation rate in agreement with previous results were raising new questions, in particular as regarding the crossover from diffusive to ballistic wires, which we answer using modified Cooperon equation. In addition, we focus on the intrinsic spin Hall effect, which is only due to spin-orbit coupling. Having shown the basic features with analytical calculations, we solve the spin Hall conductivity in presence of binary and block-distributed impurities (Anderson model). At this we apply the Kernel Polynomial Method, which allows for a finite size analysis of the metal-insulator transition and the calculation of spin Hall conductivity in large systems compared with those addressable with exact diagonalization.

Atomistic Spin Dynamics

Atomistic Spin Dynamics
Author: Olle Eriksson
Publisher: Oxford University Press
Total Pages: 265
Release: 2017
Genre: Science
ISBN: 0198788665

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Several large experimental facilities that focus on detection and probing magnetization dynamics have been realized in Europe, USA and Japan. This book covers theoretical and practical aspects of the vibrant and emerging research field of magnetization dynamics.

Handbook of Spintronics

Handbook of Spintronics
Author: Yongbing Xu
Publisher: Springer
Total Pages: 0
Release: 2015-10-14
Genre: Science
ISBN: 9789400768918

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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.

Spin Current

Spin Current
Author: Sadamichi Maekawa
Publisher: Oxford University Press
Total Pages: 541
Release: 2017
Genre: Science
ISBN: 0198787073

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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.

Magnetism and Accelerator-Based Light Sources

Magnetism and Accelerator-Based Light Sources
Author: Hervé Bulou
Publisher: Springer Nature
Total Pages: 208
Release: 2021-02-17
Genre: Science
ISBN: 3030646238

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This open access book collects the contributions of the seventh school on Magnetism and Synchrotron Radiation held in Mittelwihr, France, from 7 to 12 October 2018. It starts with an introduction to the physics of modern X-ray sources followed by a general overview of magnetism. Next, light / matter interaction in the X-ray range is covered with emphasis on different types of angular dependence of X-ray absorption spectroscopy and scattering. In the end, two domains where synchrotron radiation-based techniques led to new insights in condensed matter physics, namely spintronics and superconductivity, are discussed. The book is intended for advanced students and researchers to get acquaintance with the basic knowledge of X-ray light sources and to step into synchrotron-based techniques for magnetic studies in condensed matter physics or chemistry.

Handbook of Magnetic Materials

Handbook of Magnetic Materials
Author: K.H.J. Buschow
Publisher: Elsevier
Total Pages: 605
Release: 2007-12-15
Genre: Science
ISBN: 0080553869

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Volume 17 of the Handbook on the Properties of Magnetic Materials, as the preceding volumes, has a dual purpose. As a textbook it is intended to be of assistance to those who wish to be introduced to a given topic in the field of magnetism without the need to read the vast amount of literature published. As a work of reference it is intended for scientists active in magnetism research. To this dual purpose, Volume 17 of the Handbook is composed of topical review articles written by leading authorities. In each of these articles an extensive description is given in graphical as well as in tabular form, much emphasis being placed on the discussion of the experimental material in the framework of physics, chemistry and material science. It provides the readership with novel trends and achievements in magnetism. *composed of topical review articles written by leading authorities *intended to be of assistance to those who wish to be introduced to a given topic in the field of magnetism *as a work of reference it is intended for scientists active in magnetism research *provide the readership with novel trends and achievements in magnetism

Nanomagnetism

Nanomagnetism
Author: Claude Fermon
Publisher: John Wiley & Sons
Total Pages: 350
Release: 2016-12-28
Genre: Science
ISBN: 3527699058

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This first book to focus on the applications of nanomagnetism presents those already realized while also suggesting bold ideas for further breakthroughs. The first part is devoted to the concept of spin electronics and its use for data storage and magnetic sensing, while the second part concentrates on magnetic nanoparticles and their use in industrial environment, biological and medical applications. The third, more prospective part goes on to describe emerging applications related to spin current creation and manipulation, dynamics, spin waves and binary logic based on nano-scale magnetism. With its unique choice of topics and authors, this will appeal to academic as well as corporate researchers in a wide range of disciplines from physics via materials science to engineering, chemistry and life science.