644 research outputs found
A new diluted magnetic semiconductor: The half-metallic ferromagnet CoTi(1-x)FexSb
Half-Heusler compounds with 18 valence electrons are semi-conducting. It will
be shown that doping with electrons results in half-metallic ferromagnets,
similar to the case of diluted semi-conductors. CoTiSb is known to be a
semi-conducting Half-Heusler compound. Doping by Fe is expected to result in
ferromagnetic order. It was found that Ti can be replaced by up to about 10% Fe
while its crystal structure still remains C1b, which was proved by X-ray powder
diffraction. SQUID magnetometry revealed a magnetic moment of 0.32 mB per unit
cell at 5K.Comment: JMMM accepte
The half-metallic ferromagnet Co2Mn0.5Fe0.5Si
Electronic structure calculation were used to predict a new material for
spintronic applications. Co2Mn0.5Fe0.5Si is one example which is stable against
on-site correlation and disorder effects due to the position of the Fermi
energy in the middle of the minority band gap. Experimentally the sample were
made exhibiting L21 structure and a high magnetic order.Comment: 5 pages, 2 Figures, J. Magn. Magn. Mater. accepte
Structural, magnetic, and transport properties of CoFeSi Heusler films
We report the deposition of thin CoFeSi films by RF magnetron sputtering.
Epitaxial (100)-oriented and L2 ordered growth is observed for films grown
on MgO(100) substrates. (110)-oriented films on AlO(110) show several
epitaxial domains in the film plane. Investigation of the magnetic properties
reveals a saturation magnetization of 5.0 at low temperatures. The
temperature dependence of the resistivity exhibits a crossover
from a T^3.5 law at T<50K to a T^1.65 behaviour at elevated temperatures.
shows a small anisotropic magnetoresistive effect. A weak
dependence of the normal Hall effect on the external magnetic field indicates
the compensation of electron and hole like contributions at the Fermi surface.Comment: 10 pages, 9 figures to be published in J. Phys. D: Appl. Phy
Electronic Structure, Localization and Spin-State Transition in Cu-substituted FeSe: FeCuSe
We report density functional studies of the FeCuSe alloy done
using supercell and coherent potential approximation methods. Magnetic behavior
was investigated using the disordered local moment approach. We find that Cu
occurs in a nominal configuration and is highly disruptive to the
electronic structure of the Fe sheets. This would be consistent with a metal
insulator transition due to Anderson localization. We further find a strong
cross over from a weak moment itinerant system to a local moment magnet at . We associate this with the experimentally observed jump near
this concentration. Our results are consistent with the characterization of
this concentration dependent jump as a transition to a spin-glass
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