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 50 for “"magnetostriction"”.
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Magnetostriction in ferromagnets and antiferromagnets.
Thesis. 1977. Ph.D.--Massachusetts Institute of Technology. Dept. of Physics.
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Anisotropy and magnetostriction of GdA12 and related compounds
… the Czochralski technique. Measurements of the magnetostrictions and anisotropies of disc-shaped samples of the compounds GdAl2, Gd0.98 Tbg0.02 and Gdg0.95Tbg0.95 Al2 have been made between 4.2K and their Curie temperatures in applied magnetic fields up to 2.5T.<br/><br/>Anisotropy constants …
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Thermal expansion and magnetostriction studies on iron pnictides
… for measurements of the thermal expansion and magnetostriction of novel superconducting iron pinictides and related materials. In particular, \re~with R\,=\,La, Ce, Pr, Sm, Gd, \laf~and Ca(Fe$_{1-x}$Co$_x$)$_2$As$_2$ have been investigated. The data on polycrystalline \laf~are the first …
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Framework for a Unified Macroscale Model of Magnetostriction
… of a framework for a unified mutliscale model of magnetostriction. The lack of accurate models of macroscale hysteretic magnetostriction has inhibited the development of novel devices and savings. This thesis presents a framework for such a model. After motivating and providing the necessary …
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Design of materials with small magnetic hysteresis: the unexpected role of magnetostriction.
… influ-ence coercivity in the presence of magnetostriction, primarily because larger defects introduce stronger localized stress fields that provide more hindrance to domain-wall motion, and thus increase the coercivity. Additionally, we showed that the inclusion of magnetostriction (i.e. …
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Characterization of Bending Magnetostriction in Iron-Gallium Alloys for Nanowire Sensor Applications
This research explores the possibility of using electrochemically deposited nanowires of magnetostrictive iron-gallium (Galfenol) to mimic the sensing capabilities of biological cilia. Sensor design calls for incorporating Galfenol nanowires cantilevered from a membrane and attached to a …
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Deployment and on-orbit shape modifications for a large space telescope using magnetostriction
The Hubble Space Telescope, with its 2.4-m primary mirror, enabled notable scientific progress and discoveries, like for instance the acceleration of the expansion of the universe. Twenty-six years later, NASA is about the launch the next generation of space telescopes, namely the James Webb Space …
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Iron-gallium alloys : temperature and field effects on [lambda]100 and magnetic anisotropy measurements
Magnetostriction measurements were taken on samples of Fe-Ga alloys (Galfenol) containing between 18% and 35% Ga in fields of 5 kOe to 24 kOe from room temperature to liquid nitrogen temperature. In addition, room temperature magnetic anisotropy measurements were conducted on samples between 8% Ga …
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Magnetic Properties Of Sputter Deposited Fe-based Amorphous Thin Films For Resonator Application
… properties, including induced anisotropy and magnetostriction, of the as-deposited and annealed films using an M-H Looper. The chemical composition of the films was characterized using secondary ion mass spectroscopy (SIMS). The physical thickness of the films was determined by use of a stylus …
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Epitaxial Nd-Fe-B films: Growth, texture, magnetism and the influence of mechanical elongation
… measurements under stress. Although the magnetostriction is easily neglected in the Nd2Fe14B compound, distinguishable inverse magnetostriction was observed by conventional tensile elongation with a flexible substrate. As a result, anisotropic strain in the film, which breaks the in-plane …
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Electrodeposition of High Magnetostrictive Cobalt Iron Alloy Films for Smart Tags and Sensor Applications
… In current research looking at CoFe, improved magnetostriction was achieved using a co-sputtering, annealing, and quenching method1. Other current research has reported electrodeposited CoFe films using a sulfate based chemistry resulting in film compositions that are Fe rich in the range of …
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Desarrollo de composites magnetostrictivos de FeAl y FeGa para su aplicación en sensores de deformación
… present work a study of the effect of reverse magnetostriction on Fe-Al/polyester, Fe-Al/silicone and Fe-Ga/silicone composites is carried out for its subsequent use as a sensor element of a magnetostrictive sensor, which may allows us to measure the stresses and deformations. The magnetic …
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Mechanics of magneto-active polymers
… model is further developed to predict the magnetostriction and the MR effect of MAPs subjected to a uniform magnetic field. In general, the magnetic permeability of a MAP varies during a deformation due to the change of the microstructure. The strain dependence of permeability has been …
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Structural Investigations of Highly Strictive Materials
… to be dominant for compositions near the magnetostriction peaks in the phase diagram. Quenching was found to increase the volume fraction of nanoprecipitates for x=19, near the first magnetostriction peak. With increasing x to 22.5, nanoprecipitates were observed to undergo a D03 – B2 …
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Modeling of magnetorheological elastomers
… particles. These materials can also demonstrate magnetostriction, with large strains compared to the magnetostriction seen in crystalline solids. Ultrasoft MREs, with Young's moduli on the order of kPa or less, have characteristic pinched magnetic hysteresis loop shapes that are associated with …
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Fully Distributed Multi-Material Magnetic Sensing Structures for Multiparameter DAS Applications
… was evaluated as a function of the saturation magnetostriction constants and a total of 4 modules were used to fully characterize the complex physics involved in this sensor design. All fabrication and testing were performed in-house using a full scale 3-story fiber draw tower and custom …
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Exotic Phenomena Emerging from Localized Multipolar Degrees of Freedom
… the implementation of lattice-based probes -- magnetostriction -- to unveil hidden multipolar orderings and multipolar-based quantum spin liquid states.
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Anisotropic behaviour of magneto-electric coupling in multiferroic composites
… are proportional to the theoretical saturation magnetostriction. The samples have been magnetically characterised using a recommissioned and developed biaxial vibrating sample magnetometer, capable of detecting the component of a sample’s magnetic moment in 2 perpendicular directions and thus …
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Expanding ultrafast photoacoustics for investigation of mechanical properties and thermal transport
… was used as an acoustic transducer using demagnetostriction effect. Galfenol showed great potential as an optimal transducer for the ultrafast magnetostriction in both longitudinal and shear modes. Strained piezoelectric InGaN/GaN semiconductor superlattices were used to generate and to …
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