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Showing 1 to 20 of 40 for “"demagnetization"”.
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Element-resolved ultrafast magnetization dynamics in ferromagnetic alloys and multilayers
The microscopic origin of ultrafast demagnetization, i.e. the quenching of the magnetization of a ferromagnetic metal on a sub-picosecond timescale after laser excitation, is still only incompletely understood, despite a large body of experimental and theoretical work performed since the discovery …
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Electromagnetic fault analysis for high specific power permanent magnet synchronous machine
… temperature, the importance of permanent magnet demagnetization and long-term insulation quality is stressed. Demagnetization will be quantified using finite element methods, where the effects of permanent magnet material, air gap, and rotor back yoke material on demagnetization will be explored …
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Ultrafast laser driven spin generation in metallic ferromagnets
… spins in FM in three distinct mechanisms: (i) demagnetization; (ii) spin-dependent Seebeck effect (SDSE); (iii) optical helicity. The demagnetization-driven spin generation is due to energy transport between electrons and magnons of FM and conservation of angular momentum for electron-magnon …
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Understanding and development of combined acoustic and magnetic actuation of Ni₂MnGa single crystals
… reduced by the demagnetizing field. For a small demagnetization factor, full MFIS can be achieved at a field as low as 0.5 kOe. However, for a high demagnetization factor, full MFIS may require a field as high as 3.5 kOe. A phenomenological free energy model with an approximate magnetostatic term …
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ΓΕΩΜΑΓΝΗΤΙΚΕΣ ΜΕΛΕΤΕΣ ΣΕ ΛΙΜΝΑΙΑ ΙΖΗΜΑΤΑ
… IS OF STABLE CHARACTER PRODUCING SMOOTHY DEMAGNETIZATION CURVES, WELL GROUPED DIRECTIONS AND MEDIAN DESTRUCTIVE FIELDS RANGING BETWEEN 200 AND 500OE AFTER CLEANING WITH ALTERNATING MAGNETIC FIELDS. (SHORTENED)
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History Induced Critical Scaling in Disordered Media and Super Diffusive Growth in Highly Advective Random Environments
… the RFIM. A numerical scaling analysis of the AC demagnetization curve of the RFIM is performed, examining the effect of the underlying disorder on avalanche size distributions, correlation functions, and spanning avalanches. Furthermore, a similar scaling analysis for nested, concentric, …
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Thermometry and cooling of ultracold atoms in an optical lattice
… studies was the development of spin gradient demagnetization cooling. By performing an adiabatic drop in gradient strength while still in the superfluid, significant cooling of the entire system was observed. When the same process was performed in the Mott insulator, the spin temperature was …
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The Development of a Novel Figure of Merit to Analyze Strain-Mediated Magnetoelectric Antennas
… results presented are the effects of including demagnetization and stress distributions, and most importantly the ability of the metric to predict the change in magnetization of the device. It is shown that for aspect ratios greater than roughly 2.5 the metric trends the same as the change in …
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Nanostructured magnetic materials for integrated magnonic devices
… magnetic orientation (φ) dependent ultrafast demagnetization and precessional dynamics of electrodeposited non-exchange spring nanostructured CoP alloys. The precession frequency shows dominant two-fold anisotropy superposed with moderate four-fold anisotropy, while the Gilbert damping …
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Development of high efficiency high speed permanent magnet generator
… difficult and complicated, which leads to demagnetization and the reduction of the output power and shortens the lifetime of the critical components such as the bearings. This thesis presents the design and development of the HSPM generator. It also identifies the heat generated by means of …
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Optically induced ferro- and antiferromagnetic dynamics in the rare-earth metal dysprosium
… faster and more energy-efficient than demagnetization in ferromagnets. By probing antiferromagnetic order in time and space, it is found to be affected along the whole sample depth of an in situ grown 73 nm tick Dy film. Interatomic transfer of angular momentum via fast diffusion of …
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A Numerical Study of Dynamic Micromagnetics
… fields, exchange field, anisotropy field, demagnetization field and applied field. Based on the related algorithms for programming given, a set of software for micromagnetics calculation is developed successfully in C++. Several attempts are also made to reduce the calculation complexity. …
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Ground states in artificial spin ice
… which previously-used techniques such as ac demagnetization were unable to do. Second, the shakti lattice, a new lattice geometry that better mimics the behavior of real spin ice, is described. Third, a series of experiments using artificial spin ice to explore memory effects in hysteretic …
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Hysteresis phenomena of ferromagnetic bodies using the nonlocal exchange energy model
… hysteresis subloops, Barkhausen effect, and demagnetization. The results are in three parts. First, we examine analytically the problem of a unit sphere of ferromagnetic material. We show that when the exchange energy is zero we duplicate De Simone's model which has a wide range of …
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DETECTION OF MAGNETIZATION REVERSAL IN A NEODYMIUM-IRON-BORON MAGNET USING A HALL-EFFECT MICROPROBE
… upon the blank probe signal) in the demagnetization of a fully magnetized magnet. Magnetization traces for a thermally demagnetized Nd-Fe-B magnet did not exhibit measurable Barkhausen steps until a field of approximately 1.2 T was applied. The following observations were made for two …
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A paleomagnetic study of early tertiary basalts in West Texas
… Stability of magnetization was established by ac demagnetization. Because of large secondary magnetic components and chemical alteration it was not possible to obtain reliable remanent magnetic directions or pole positions for sixteen flows. Of the fifteen reliable flows, six are normally …
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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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MAGNETIC DATING OF VESUVIAN LAVAS
… the W, S and SE slopes of the volcano. Thermal demagnetization of 3 component IRMs, susceptibility measurements and coercivity analyses have been carried out on one pilot specimen per site in order to identify the magnetic carriers and to estimate the magnetic grain size. The identificatìon of …
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Thermal Modeling and Validation Testing of a Miniature Xenon Ion Thruster
… <p>to the permanent magnets in order to postpone demagnetization, which occurs at</p> <p>300C. Sheathing the entire keeper electrode with Macor was shown to reduce the</p> <p>temperature by as much as 13.3C at certain times and locations. Due to its lower</p> <p>thermal conductivity, it was …
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