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Author

Ahmad Omar

Bio: Ahmad Omar is an academic researcher. The author has contributed to research in topics: Cobalt. The author has an hindex of 1, co-authored 1 publications receiving 4 citations.
Topics: Cobalt

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Journal ArticleDOI
01 Oct 1971-Nature
TL;DR: Lipson and Steeple as mentioned in this paper interpreted X-ray powder diffraction patterns and found that powder-diffraction patterns can be represented by a set of 3-dimensional planes.
Abstract: Interpretation of X-ray Powder Diffraction Patterns . By H. Lipson and H. Steeple. Pp. viii + 335 + 3 plates. (Mac-millan: London; St Martins Press: New York, May 1970.) £4.

1,867 citations

Posted Content
TL;DR: Half-metallic antiferromagnets as a subclass of half-metals are characterized further by totally compensated spin moments in a unit cell, and have the advantage of being able to generate fully spin-polarized current while exhibiting zero macroscopic magnetization.
Abstract: Spintronics is expected as the next-generation technology based on the novel notch of spin degree of freedom of electrons. Half metals, a class of materials which behave as a metal in one spin direction and an insulator in the opposite spin direction, are ideal for spintronic applications. Half metallic antiferromagnets as a subclass of half metals are characterized further by totally compensated spin moments in a unit cell, and have the advantage of being able to generate fully spin-polarized current while exhibiting zero macroscopic magnetization. Considerable efforts have been devoted to the search for this novel material, from which we may get useful hints for prospective material exploration.

15 citations

Journal Article
TL;DR: In this paper, the spin-projected conductivity components are calculated based on the Kubo-Greenwood formalism, and it is shown that even a small substitution of some other transition element instead of Mn may lead to a substantial increase in spin polarization along the tetragonal axis.
Abstract: Our study highlights spin-polarization mechanisms in metals by focusing on the mobilities of conducting electrons with different spins instead of their quantities. Here, we engineer electron mobility by applying chemical disorder induced by nonstoichiometric variations. As a practical example, we discuss the scheme that establishes such variations in tetragonal ${\\mathrm{Mn}}_{3}\\mathrm{Ga}$ Heusler material. We justify this approach using first-principles calculations of the spin-projected conductivity components based on the Kubo-Greenwood formalism. It follows that, in the majority of cases, even a small substitution of some other transition element instead of Mn may lead to a substantial increase in spin polarization along the tetragonal axis.

11 citations

Proceedings ArticleDOI
06 Jun 2012
TL;DR: In this article, the anti-site disorder in polycrystalline sample Co2FeGe was investigated using the full-professor method and the lattice parameter was observed to be 5.738 A and 5.729 A for RT and 5 K respectively.
Abstract: Neutron diffraction studies have been carried on the polycrystalline sample Co2FeGe to investigate its structural and magnetic property. Earlier X-ray studies revealed that the system crystallizes in cubic L21 structure but detail investigation of anti-site disorder in this material is presented. The Rietveld refinement on the powder neutron diffraction was carried out using Full Prof method and the lattice parameter was observed to be 5.738 A and 5.729 A for RT and 5 K respectively. Further, magnetic structure analysis shows that the Co and Fe moments align ferromagnetically. The sub lattice moments were observed to be Co 1.67 μB and Fe 2.50 μB at room temperature where as at 5 K sublattice moments were observed to be Co 1.96 μB and Fe 2.56 μB.

2 citations