Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"Magnetization Reversal"”.
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Field and current induced magnetization reversal in patterned Pseudo Spin Valve devices
The field and current induced magnetization switchings of Pseudo-Spin-Valve (PSV) devices are described in this dissertation. An aligned sequence of three (one optical and two electron-beam) lithographies was used to define the devices and their electrical contacts. The PSV stack comprised a layer …
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DETECTION OF MAGNETIZATION REVERSAL IN A NEODYMIUM-IRON-BORON MAGNET USING A HALL-EFFECT MICROPROBE
Magnetization processes in a sintered Nd-Fe-B permanent magnet (NEOMAX-35) were examined on a small scale using a Hall-effect microprobe with an active area 75 μm on a side. Probes were made by evaporating bismuth through a stencil mask onto glass slides. Experiments were performed by placing a …
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Characterization of Magnetic Nanostructured Materials by First Order Reversal Curve Method
<p>The Interactions and magnetization reversal of Ni nanowire arrays and synthetic anit-ferromagnetic coupled thin film trilayers have been investigated through first order reversal curve (FORC) method. By using a quantitative analysis of the local interaction field profile distributions obtained …
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Study of Magnetization Switching for MRAM Based Memory Technologies
Understanding magnetization reversal is very important in designing high density and high data transfer rate recording media. This research has been motivated by interest in developing new nonvolatile data storage solutions as magnetic random access memories - MRAMs. This dissertation is intended …
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NONLINEAR SPIN DYNAMICS AND ULTRA-FAST PRECESSIONAL SWITCHING
… is intended to provide a theoretical analysis of magnetization dynamics in nanometer scale structures over picosecond time scales. This research has been motivated by promising technological applications in the area of magnetic data storage, as well as by pure scientific quest for ultra-fast spin …
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Using avalanche statistics to forecast failure in models of earthquake faults and magnets
… models of disordered magnets which yield giant magnetization-reversal avalanches, which may have applications to predicting failures in power grid networks.
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Study of microwave-assisted magnetization dynamics in magnetic films and structures
Microwave-assisted magnetization reversal (MAMR) has been suggested as an alternative recording scheme to extend areal densities in hard disk drives beyond 1 Tb/in<sup>2</sup>. In this thesis, microwave-assisted magnetization dynamics have been characterized in different spatial regimes by …
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Field induced switching in multilayer rhombic magnetic rings
… states exhibited within these devices. The magnetization reversal characteristics of these structures are explored in an effort to fully understand interactions occurring within the devices and their resulting effect on giant magnetoresistance (GMR). Contact configuration and angular …
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Magnetic reversal of artificial spin ice
… studies that center around the magnetic reversal of artificial spin ice arrays. First, I investigate the magnetic response of permalloy brickwork artificial spin ice. Through the systematic study of the transport properties for finely varied magnetic field directions, I find that the …
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Magnetic nanostructures patterned by block copolymer lithography
… block copolymer masks and examining the magnetic reversal mechanisms of as deposited and patterned magnetic films. Ti / Co 66 at. % Cr 22 at. % Pt 12 at. % (CoCrPt) films with perpendicular magnetic anisotropy were deposited on silicon wafers by UHV sputtering. Ti was used as an adhesion layer and …
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Magnetic and Mechanical Properties of Ultrasoft Magnetorheological Elastomers
… <p>The effect of polymer stiffness on magnetization reversal of MREs has been investigated using a combination of magnetometry measurements and computational modeling. The magnetic hysteresis loops of the softer MREs exhibit a characteristic pinched loop shape with almost zero remanence …
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Fundamentals, Voltage Control and Novel Application of Exchange Bias in Magnetic Thin Films
… effects of EB on nucleation and propagation of magnetization reversal. We discover that nucleation and propagation EB can be unequal and demonstrate how that can lead to unexpected behavior of the system, including having asymmetric hysteresis loops. Building on these insights, we demonstrate …
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Magnetism and interactions within the single domain limit: reversal, logic and information storage
… paves way for its application. In addition, the magnetization reversal in perpendicular magnetic anisotropy (PMA) system and its dependence on scaling law were studied. High quality epitaxial L10 FePdPt and FePt thin films on MgO (001) substrate was fabricated. For FePd binary alloy thin films, …
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Hybrid spintronics and straintronics: An ultra-low-energy computing paradigm
… dissertation, it is shown theoretically that the magnetization of two-phase multiferroic single-domain nanomagnets can be switched very energy-efficiently, more so than any device currently extant, leading possibly to new magnetic logic and memory systems which might be an important contributor to …
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High-Nuclearity Lanthanide(III) Complexes as Single-Molecule Magnets and Luminescent Materials
… vertex. The {DyIII7} analogue exhibits slow magnetization relaxation, whereas all heptanuclear compounds show ligand-centered blue-green emissions. The second project of this thesis, which is discussed in Chapter 3, comprises the first use of the Schiff base ligand …
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Structural and magnetic characterization of Nd-based Nd-Fe and Nd-Fe-Co-Al metastable alloys
… nanocrystallites in an amorphous phase. The demagnetization curves the hard magnetic Nd80Fe20 measured at temperatures above 30 K are typical of a hard magnetic material. The coercivity increases from 0.48 to 4.4 T with the temperature decreasing from 300 to 55 K. The demagnetization curves …
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Nanostructured magnetic materials for integrated magnonic devices
… coercivities in thicker films. The First Order Reversal Curve (FORC) distributions demonstrate various reversal mechanisms within the samples, confirming the transition between non-ES and ES states based on the prevalent interfacial exchange coupling. Additionally, the field-dependent Brillouin …
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Investigation of spin-caloric and spin-orbit torque materials by vectorial spin Seebeck measurements and an advanced x-ray magnetic reflectivity analysis
… induces a spin-orbit torque (SOT) on the magnetization. Phenomena like the ISGE take advantage of the relativistic momentum transfer between electron and spin just as another key mechanism of spin-orbitronics in form of the so called spin Hall effect (SHE). Here, an electric current …
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Modeling Shape Effects in Nano Magnetic Materials With Web Based Micromagnetics
… various widths. The in-plane hysteresis loop and reversal behavior have no notable difference in direction parallel to the cross-tie, but greatly changed in perpendicular and diagonal directions. The switching field distribution is significantly reduced. The two distinct "onion" bit states of the …