Spin Dynamics in Confined Magnetic Structures II

Spin Dynamics in Confined Magnetic Structures II
Author: Burkard Hillebrands
Publisher: Springer Science & Business Media
Total Pages: 343
Release: 2003-09-04
Genre: Science
ISBN: 3540460977

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This second volume of the book on spin dynamics in confined magnetic structures covers central aspects of spin dynamic phenomena, so that researchers can find a comprehensive compilation of the current work in the field. Introductory chapters help newcomers to understand the basic concepts, and the more advanced chapters give the current state of the art for most spin dynamic issues in the milliseconds to femtoseconds range. Both experimental techniques and theoretical work are discussed. The comprehensive presentation of these developments makes this volume very timely and valuable for every researcher working in the field of magnetism. It describes the new experimental techniques which have advanced this field very rapidly. Among the techniques covered, particular attention is given to those involving high temporal, elemental and spatial resolution as well as to techniques involving magnetic field pulses with very short rise times and durations.

Understanding Spin Dynamics

Understanding Spin Dynamics
Author: Danuta Kruk
Publisher: CRC Press
Total Pages: 264
Release: 2015-10-22
Genre: Science
ISBN: 9814463507

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Experimental methods employing spin resonance effects (nuclear magnetic resonance and electron spin resonance) are broadly used in molecular science due to their unique potential to reveal mechanisms of molecular motion, structure, and interactions. The developed techniques bring together biologists investigating dynamics of proteins, material scie

Exciton Transport Phenomena in GaAs Coupled Quantum Wells

Exciton Transport Phenomena in GaAs Coupled Quantum Wells
Author: Jason Leonard
Publisher: Springer
Total Pages: 67
Release: 2017-11-02
Genre: Technology & Engineering
ISBN: 3319697331

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This thesis presents results crucial to the emerging field of indirect excitons. These specially designed quasiparticles give the unique opportunity to study fundamental properties of quantum degenerate Bose gases in semiconductors. Furthermore, indirect excitons allow for the creation of novel optoelectronic devices where excitons are used in place of electrons. Excitonic devices are explored for the development of advanced signal processing seamlessly coupled with optical communication. The thesis presents and describes the author's imaging experiments that led to the discovery of spin transport of excitons. The many firsts presented herein include the first studies of an excitonic conveyer, leading to the discovery of the dynamical localization-delocalization transition for excitons, and the first excitonic ramp and excitonic diode with no energy-dissipating voltage gradient.

Spin Dynamics in Confined Magnetic Structures I

Spin Dynamics in Confined Magnetic Structures I
Author: Burkard Hillebrands
Publisher: Springer Science & Business Media
Total Pages: 363
Release: 2001-11-06
Genre: Science
ISBN: 3540411917

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Introductory chapters help newcomers to understand the basic concepts, and the more advanced chapters give the current state of the art for most spin dynamic issues in the milliseconds to femtoseconds range. Emphasis is placed on both the discussion of the experimental techniques and on the theoretical work. The comprehensive presentation of these developments makes this volume very timely and valuable for every researcher working in the field of magnetism.

Spin Dynamics in Confined Magnetic Structures I

Spin Dynamics in Confined Magnetic Structures I
Author: Burkard Hillebrands
Publisher: Springer Science & Business Media
Total Pages: 363
Release: 2003-07-01
Genre: Science
ISBN: 3540409076

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Introductory chapters help newcomers to understand the basic concepts, and the more advanced chapters give the current state of the art for most spin dynamic issues in the milliseconds to femtoseconds range. Emphasis is placed on both the discussion of the experimental techniques and on the theoretical work. The comprehensive presentation of these developments makes this volume very timely and valuable for every researcher working in the field of magnetism.

Probing Spin Dynamics and Transport Using Ferromagnetic Resonance Based Techniques

Probing Spin Dynamics and Transport Using Ferromagnetic Resonance Based Techniques
Author: Chunhui Du
Publisher:
Total Pages: 137
Release: 2015
Genre:
ISBN:

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Generation and manipulation of spin is of central importance in modern physics. This intense interest is driven in part by exciting new phenomena in spintronics such as spin Hall effects and spin transfer torque as well as by the growth in new tools enabling microscopic studies. Ferromagnetic resonance (FMR) is a powerful technique to study macro-scale spin ensembles, and an effective method to generate pure spin currents. Combined with scanning capability, it can be used as a spin sensitive microscopy with nano-scale spatial resolution to bring fresh insights in spintronics and achieve local excitation, manipulation, and detection of spin. In the first part of this thesis, I will briefly introduce the field of spintronics. In the second chapter, I demonstrate the use of FMR spectroscopy to study the static and dynamics properties of novel materials. In the third chapter, I present the FMR spin pumping technique in ferromagnetic material/normal metal bilayer to characterize the spin Hall angles for a series of 3d, 4d, and 5d transition metals with widely varying spin-orbit coupling strengths and demonstrate that both atomic number, Z, and d electron count play important roles in spin Hall physics. Those work studies the spin dynamics and transport across the interface defined by material discontinuity in macro-scale sample. To study nano-scale structures, in the forth and fifth chapters, I describe probing and imaging spin dynamics using spin wave modes confined into microscopic volumes in a ferromagnetic film by the spatially inhomogeneous magnetic field of a scanned micromagnetic tip of a ferromagnetic resonance force microscope (FMRFM). It shows the characteristics of the localized mode can be broadly tuned by appropriate selection of the orientation of the tip moment relative to the applied uniform field. Micromagnetic simulations accurately reproduce our experimental results and allow quantitative understanding of the ferromagnetic resonance force microscopy spectra. These results provide a universal method of generating and understanding the tightly confined localized modes in various measurement geometries and material systems with increased freedom in the choice of tip and material, and paves the way to improved spatial resolution for imaging using localized spin wave modes. At last, I demonstrate a design of room temperature FMR force microscope with both imaging and transport capability to study and image spin dynamics and transport across the interface defined by the magnetic textures with nano-scale resolution. The sixth chapter is a conclusion of the entire dissertation.

Spin Dynamics in Two-Dimensional Quantum Materials

Spin Dynamics in Two-Dimensional Quantum Materials
Author: Marc Vila Tusell
Publisher: Springer Nature
Total Pages: 169
Release: 2021-11-10
Genre: Technology & Engineering
ISBN: 3030861147

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This thesis focuses on the exploration of nontrivial spin dynamics in graphene-based devices and topological materials, using realistic theoretical models and state-of-the-art quantum transport methodologies. The main outcomes of this work are: (i) the analysis of the crossover from diffusive to ballistic spin transport regimes in ultraclean graphene nonlocal devices, and (ii) investigation of spin transport and spin dynamics phenomena (such as the (quantum) spin Hall effect) in novel topological materials, such as monolayer Weyl semimetals WeTe2 and MoTe2. Indeed, the ballistic spin transport results are key for further interpretation of ultraclean spintronic devices, and will enable extracting precise values of spin diffusion lengths in diffusive transport and guide experiments in the (quasi)ballistic regime. Furthermore, the thesis provides an in-depth theoretical interpretation of puzzling huge measured efficiencies of the spin Hall effect in MoTe2, as well as a prediction of a novel canted quantum spin Hall effect in WTe2 with spins pointing in the yz plane.

Interactions Between Spin Transport and Dynamics Studied Using Spatially Resolved Imaging and Magnetic Resonance

Interactions Between Spin Transport and Dynamics Studied Using Spatially Resolved Imaging and Magnetic Resonance
Author: Michael Roy Page
Publisher:
Total Pages: 234
Release: 2016
Genre:
ISBN:

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In this dissertation, I explore the interactions that occur between transported spins and magnetization dynamics using spatially resolved imaging and magnetic resonance. The integration of spin transport and dynamics will be a crucial aspect of realizing spintronic devices, which seek to improve upon current charge based electronics. Rather than focusing on the charge degree of freedom as in traditional electronics, spintronics seeks to utilize the properties of the electron spin degree of freedom to revolutionize the fundamental operating principles of data processing and storage devices. Spintronics promises greater functionality and energy efficiency in devices based on electron spin. However, improved understanding and control of the spin degree of freedom is required for spintronics to reach its full potential. The work in this dissertation represents efforts towards addressing these requirements. I discuss my work relating to the development of a custom scanned probe microscope allowing simultaneous spatially resolved imaging while imposing transport in electrically active spintronic devices. Using this microscope, I correlate the switching of magnetic electrodes in a graphene spin valve to the resistance states by directly imaging the electrode magnetization configuration while simultaneously measuring the non-local magnetoresistance. I investigate interactions between a ferromagnet driven into resonance and proximal nitrogen vacancy centers in diamond. Spinwaves generated during the decay of the uniform mode driven to ferromagnetic resonance relax the diamond nitrogen vacancy center spins resulting in a change in the fluorescence intensity. This technique allows the study of transport of angular momentum between two separated spin systems, as well as the possibility for the nanoscale imaging of magnetization dynamics. I demonstrate Heusler alloy ferromagnetic materials as high spin polarization spin injectors for device applications by studying their magnetoresistive output as a function of composition at room and low temperatures. Spin injection efficiency is another important aspect in the performance of spintronic devices, and optimization of spin injection will be of importance in creating realistic devices. Another promising avenue for spin injection relies on the spin Hall effect. I discuss efforts at using the spin Hall effect in platinum to inject spins into an aluminum channel to be detected in another platinum electrode by the inverse spin Hall effect without the need for a ferromagnet, thus reducing complications resulting from the stray field of typical ferromagnetic injectors. I discuss exploration of spin pumping devices based on metallic and insulating ferromagnet/graphene bilayers using ferromagnetic resonance and electrical detection of the inverse spin Hall effect. Spin pumping represents another opportunity to study interactions of spin transport and magnetization dynamics, in this case leveraged for efficient spin injection. Finally, I perform magnetic resonance measurements of thin film iron germanium skyrmionic candidate materials. Skrymions are a candidate for high density and low power magnetic recording. Measuring the dynamics of these materials will be important for a full characterization of their properties. I demonstrate detection of multiple magnetic phases in this material, and show evidence of large internal fields, which may be of interest in stabilizing skrymions in thin films.