Search for dissertations about: "demagnetization"

Showing result 6 - 10 of 28 swedish dissertations containing the word demagnetization.

2. 6. On the System Optimization of Magnetic Circuit with Alternative Permanent Magnets and its Demagnetization

   Author : Jonathan Sjölund; Sandra Eriksson; Leijon Mats; Sami Ruoho; Uppsala universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Permanent magnet machines; Finite element method; ferrite permanent magnets; linear machines; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

   Abstract : Permanent magnet (PM) machines are often associated with the usage of rare earth magnets, due to their high energy density. One such rare earth magnet is the neodymium-iron-boron (NdFeB), which is mainly produced in China. Due to the global scarcity of the rare earth magnets, much interest is put into utilizing other permanent magnet materials. READ MORE

4. 7. Superdiffusive Spin Transport and Ultrafast Magnetization Dynamics : Femtosecond spin transport as the route to ultrafast spintronics

   Author : Marco Battiato; Olle Eriksson; Hardy Gross; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Ultrafast magnetisation dynamics; anomalous diffusion; femtosecond dynamics; magnetism; Materialvetenskap; Materials Science;

   Abstract : The debate over the origin of the ultrafast demagnetization has been intensively active for the past 16 years. Several microscopic mechanisms have been proposed but none has managed so far to provide direct and incontrovertible evidences of their validity. READ MORE

5. 8. Ultrafast Magnetization Dynamics : Element-selective studies of magnetic alloys using ultra short XUV pulses

   Author : Rameez Saeed Malik; Olof Karis; Uwe Bovensiepen; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; magnetization dynamics; magnetic alloys; HHG; ultrashort laser pulses; magneto-optical Kerr effect MOKE ; Gilbert damping; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Abstract : In this thesis, I investigate the ultrafast magnetization dynamics in 3d ferromagnets and their alloys with ultrashort laser pulses. The high harmonics generation (HHG) setup provides extreme-ultraviolet photons with energies 35-72 eV, which is the energy range where 3d metals have their M2,3 absorption edges. READ MORE

6. 9. Ultrafast spin dynamics and relaxation in metallic ferromagnets

   Author : Vivek Unikandanunni; Stefano Bonetti; Olof Karis; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Magnetization dynamics; Three temperature model; Cobalt; Anisotropy; Electron-phonon coupling; THz; Platinum; Silver; fysik; Physics;

   Abstract : We performed ultrafast demagnetization measurements on epitaxial hcp-cobalt thin film with the easy axis in the plane of the film by pumping the sample with 400 nm radiation and probing the magneto-optic effects in the longitudinal magneto optic Kerr effect geometry using 800 nm radiation. The in-plane magnetic anisotropy of the sample enabled us to measure the demagnetization dynamics along two different crystalline directions, namely along the easy axis and at 45 degrees between the easy and hard axes. READ MORE

7. 10. Design of Rare Earth Free Permanent Magnet Generators

   Author : Petter Eklund; Sandra Eriksson; Leijon Mats; Marcus Berg; Oskar Wallmark; Uppsala universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; permanent magnet generators; electrical machine design; ferrite permanent magnet; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

   Abstract : Low speed permanent magnet (PM) synchronous generators (SGs) are commonly used in renewable energy. Rare earth (RE) PMs such as neodymium-iron-boron are a popular choice due to their high performance. READ MORE