Search for dissertations about: "ferromagnetic materials"

Showing result 16 - 20 of 106 swedish dissertations containing the words ferromagnetic materials.

2. 16. Defect Induced Room-Temperature Ferromagnetism in ZnO and MgO Thin FIlms and Device Development

   Author : Mukes Kapilashrami; Lyuba Belova; E Dan Dahlberg; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Room-temperature ferromagnetism; intrinsic defects; un-balanced balanced magnetron sputtering; magnetic anisotropy and photoconductivity; Materials science; Teknisk materialvetenskap;

   Abstract : This thesis presents the discovery of defect induced room-temperature ferromagnetism in industrially important ZnO and MgO thin films, and establishes from a systematic study, in both ZnO and MgO films, the unique phenomenon of the sequences of transitions from ferromagnetism to para-, and eventually the well known diamagnetism of the bulk as a function of film thickness. Highly oriented and high quality dense thin films of ZnO and MgO have been deposited by reactive (balanced) magnetron sputtering under different ambience conditions and deposition temperatures. READ MORE

4. 17. Magnetism of Semiconductors and Metallic Multilayers

   Author : Victor Stanciu; Per Nordblad; Peter Svedlindh; Poul Erik Lindelof; Uppsala universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; Magnetic order; Curie temperature; magnetic anisotropy; diluted magnetic III-V semiconductors; metallic magnetic multilayers; interlayer exchange coupling; Materialvetenskap; Materials science; Teknisk materialvetenskap;

   Abstract : Magnetic properties of diluted magnetic semiconductors and magnetic metallic multilayers are investigated by SQUID magnetometry. By doping GaAs with magnetic Mn2+ ions under well defined growth conditions, one obtains a diluted magnetic semiconductor, (Ga,Mn)As, in which the randomly-distributed magnetic ions act as acceptor centers. READ MORE

5. 18. Relativenobility of precipitated phases in stainless steels : Evaluation with a combination of local probing techniques

   Author : Namurata Sathirachinda; Jinshan Pan; Thomas Ladwein; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; Teknisk materialvetenskap;

   Abstract : Stainless steels often exhibit complex transformation and precipitation behaviour due to a high content of alloying elements. Secondary phases can be formed in the temperature range of 300-1000°C and are generally undesirable due to their detrimental effect on mechanical properties and corrosion resistance of stainless steels. READ MORE

6. 19. Hydrogen incorporation in Zintl phases and transition metal oxides- new environments for the lightest element in solid state chemistry

   Author : Reji Nedum Kandathil; Ulrich Häussermann; Michael A. Hayward; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Zintl phases; metal hydrides; transition metal oxyhydrides; XRPD; NPD; Rietveld refinement; Materials Chemistry; materialkemi;

   Abstract : This PhD thesis presents investigations of hydrogen incorporation in Zintl phases and transition metal oxides. Hydrogenous Zintl phases can serve as important model systems for fundamental studies of hydrogen-metal interactions, while at the same time hydrogen-induced chemical structure and physical property changes provide exciting prospects for materials science. READ MORE

7. 20. Building crystals out of crystals : Synthesis, structure and magnetic properties of iron oxide nanoparticles and self-assembled mesocrystals

   Author : Erik Wetterskog; Lennart Bergström; Markus Niederberger; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; iron oxide; nanoparticle; synthesis; self-assembly; characterization; electron microscopy; scattering; magnetic properties; Materials Chemistry; materialkemi;

   Abstract : This thesis is focused on the fabrication and characterization of self-assembled arrays of magnetic iron oxide (Fe3O4, γ-Fe2O3 and Fe1-xO) nanoparticles. The synthesis of spherical and cubic iron oxide nanocrystals, with sizes between 5 and 30 nm and narrow size distributions, is demonstrated, along with a rigorous morphological characterization of the cubic nanoparticles. READ MORE