Sökning: "magnetic semiconductors"

Visar resultat 1 - 5 av 52 avhandlingar innehållade orden magnetic semiconductors.

1. 1. Fundamental Properties of Functional Magnetic Materials

   Författare :Magnus Wikberg; Peter Svedlindh; Per Nordblad; Klas Gunnarsson; Amílcar Labarta; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetic anisotropy; magnetic aging; magnetic semiconductors; exchange interactions; magnetic oxides; spin glasses; lithium-ion batteries; short-range magnetic order; Physics; Fysik; Engineering Science with specialization in Solid State Physics; Teknisk fysik med inriktning mot fasta tillståndets fysik;

   Sammanfattning : Magnetic properties of powders, thin films and single crystals have been investigated using magnetometry methods. This thesis provides analysis and conclusions that are supported by the results obtained from spectroscopic and diffraction measurements as well as from theoretical calculations. LÄS MER

3. 2. Magnetism of Semiconductors and Metallic Multilayers

   Författare :Victor Stanciu; Per Nordblad; Peter Svedlindh; Poul Erik Lindelof; Uppsala universitet; []
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER

4. 3. Computational Material Design : Diluted Magnetic Semiconductors for Spintronics

   Författare :Lunmei Huang; Rajeev Ahuja; Walter Temmerman; Uppsala universitet; []
   Nyckelord :Physics; Density functional theory; Diluted magnetic semiconductor; Ferromagnetism; Defect; Phase transition; High pressure; Thermal elastic constant; Fysik;

   Sammanfattning : The present thesis deals with the application of ab-initio electronic structure calculations based on density functional theory for material design.The correlation between magnetic properties and electronic structures has been investigated in detail for diluted magnetic semiconductors (DMS), which have promising application for spintronics devices. LÄS MER

5. 4. Quantum mechanical models of nanomagnetism in transition metal clusters and diluted magnetic semiconductors

   Författare :Olof Strandberg; Matematisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; diluted magnetic semiconductors; Mn As; Ga; transition metal clusters; magnetic anisotropy; Nanomagnetism; quantum geometric phases; Chern numbers; effective spin Hamiltonians; dimers;

   Sammanfattning : This dissertation investigates nanomagnetism in small transition metal clusters and the diluted magnetic semiconductor (Ga,Mn)As. We derive quantum mechanical models aimed at a realistic description of the low energy physics in these systems. LÄS MER

7. 5. Magnetic solotronics near the surface of a semiconductor and a topological insulator

   Författare :Mohammad Reza Mahani; C.M. Canali; Biplab Sanyal; Linnéuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetic solotronics; Transition metal dopants; Dilute magnetism in semiconductors and topological insulators; Atomistic tight-binding models; DFT; Spin dynamics; Magnetic anisotropy; Scanning tunneling microscope.; Condensed Matter Physics; Kondenserade materians fysik;

   Sammanfattning : Technology where a solitary dopant acts as the active component of an opto-electronic device is an emerging  field known as solotronics, and bears the promise to revolutionize the way in which information is stored, processed and transmitted. Magnetic doped semiconductors and in particular (Ga, Mn)As, the archetype of dilute magnetic semiconductors, and topological insulators (TIs), a new phase of quantum matter with unconventional characteristics, are two classes of quantum materials that have the potential to advance spin-electronics technology. LÄS MER