Sökning: "ultrafast magnetization dynamics"

Visar resultat 1 - 5 av 14 avhandlingar innehållade orden ultrafast magnetization dynamics.

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

    Författare :Rameez Saeed Malik; Olof Karis; Uwe Bovensiepen; Uppsala universitet; []
    Nyckelord :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;

    Sammanfattning : 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. LÄS MER

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

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

    Sammanfattning : 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. LÄS MER

  4. 3. Magnetization dynamics of complex magnetic materials by atomistic spin dynamics simulations

    Författare :Raghuveer Chimata; Biplab Sanyal; Olle Eriksson; Koopmans Bert; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ultrafast remagnetization; ultrafast dynamics; magnetism; multiferroics; amorphous alloys; DFT; spinels magnetostriction; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : In recent years, there has been an intense interest in understanding the microscopic mechanism of laser induced ultrafast magnetization dynamics in picosecond time scales. Magnetization switching on such a time scale has potential to be a significant boost for the data storage industry. LÄS MER

  5. 4. Atomistic Spin Dynamics, Theory and Applications

    Författare :Johan Hellsvik; Olle Eriksson; Lars Nordström; Ulrich Nowak; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ab initio calculations; spin dynamics; magnetization; magnetic switching; diluted magnetic semiconductors; spin glasses; ferromagnetic relaxation; ferrimagnets; antiferromagnets; Magnetism; Magnetism; Condensed matter physics; Kondenserade materiens fysik; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : The topic of this Thesis is magnetization dynamics on atomic length scales. A computational scheme, Atomistic Spin Dynamics, based on density functional theory, the adiabatic approximation and the atomic moment approximation is presented. LÄS MER

  7. 5. Ultrafast spin dynamics and relaxation in metallic ferromagnets

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

    Sammanfattning : 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. LÄS MER