12 research outputs found
Coulomb Correlations and Magnetic Anisotropy in ordered CoPt and FePt alloys
We present results of the magneto-crystalline anisotropy energy (MAE)
calculations for chemically ordered CoPt and FePt alloys taking into
account the effects of strong electronic correlations and spin-orbit coupling.
The local spin density + Hubbard U approximation (LSDA+U) is shown to provide a
consistent picture of the magnetic ground state properties when intra-atomic
Coulomb correlations are included for both 3 and 5 elements. Our results
demonstrate significant and complex contribution of correlation effects to
large MAE of these material.Comment: revised version; 4 pages, 2 figure
Appearance of itinerant electrons detected by IR spectroscopy and its correlation with surface magnetism in Co-doped TiO2 nanopowders
IR absorption and magnetic data for the titanium dioxide nanopowders are studied. Additional absorption in IR range is revealed in nanocrystalline TiO2 and Co-doped TiO2 after reducing annealing and explained by appearance of the oxygen vacancies and delocalised charge carriers. Increasing of the absorption in IR range after annealing of Co-doped TiO2 in vacuum (or decreasing of this contribution after annealing in air) correlates with arising (or vanishing) of ferromagnetic contribution