الفهرس يوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
Using the DFT based computer package Wien2K we studied the electronic structure of some full and half
Heusler alloys.
We studied the Co based Full Heusler alloys Co2YGa)Y=TI, V, Cr, Mn, and Fe (and Co2TiZ )Z =Ga, Si, Sn (to
examine the effect of changing the Y site and the Z site on the electronic structure and magnetism of these alloys.
All of these alloys show energy gaps near the Fermi level in the minority spins and some of them are true half metals.
Also,all of them show significant magnetic moment. It is observed that changing the Y site has a major effect on the electronic structure, total magnetic moment and magnetic moment of the Co atoms in the alloys .Changing the Z element is not very effective. However, good choice of the Z element helps to obtain an energy gap surrounding the Fermi level in the minority spins.
We studied five structures for the half Heusler alloy NiMnSb, in order to test the effect of changing the atomic
sites and the lattice constant on the half metallicity and magnetism of this compound, and Heusler alloys in
general.
It is observed that changing the atomic sites cause distract change in the electronic structure and magnetic
moments.However, slight variation of the lattice constant results in slight up/downward shift in the energy bands but it affects the half metallicity We present the electronic states that surround the minority band and it is shown that all of them are either Ni-d stated or Mn-d states.
This supports that the gap in the minority spin is produced mainly because of the hybridization between the d stated of Ni and Mn .This could be generalized for half metallic Heusler alloys.