Physics

Permanent URI for this collectionhttps://repository.chuka.ac.ke/handle/chuka/431

Browse

Browsing Physics by Subject "Alloys"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    First-Principle investigation of the structural, electronic and magnetic properties of Co2VIn and CoVIn Heusler compounds
    (2017-01-05) Muthui, Zipporah1,2,a),b); Pathak, Rohit2,a); Musembi, Robinson1,a); Mwabora, Julius1,a); Skomski, Ralph3,a); Kashyap, Arti2,a),c)
    Investigation of the structural, electronic and magnetic properties of full-Heusler Co2VIn as well as half-Heusler CoVIn Cobalt based Heusler compounds using density functional theory (DFT) leads to the general conclusion that Co2VIn and CoVIn are half-metallic materials with a gap at the Fermi level in the minority states and majority states respectively. A Hubbard-like Coulomb correlation term U has been included in the DFT (DFT+U) for the computation of the electronic and magnetic properties of the compounds. The structural properties have been calculated for the paramagnetic and ferromagnetic phases, and both Co2VIn and CoVIn are found to be stable in the ferromagnetic phase. The calculated magnetic moments are 2 μB2 μB and 0.9 μB0.9 μB per formula unit for Co2VIn and CoVIn respectively.
  • Thumbnail Image
    Item
    Perpendicular magnetic anisotropy in Mn2VIn (001) films: An ab initio study
    (2017-12-07) Muthui, Zipporah1,2,3,a),b); Musembi, Robinson1,a); Mwabora, Julius1,a); Kashyap, Arti2,a),c)
    First principles study of the magnetic anisotropy of Mn2VIn (001) films show perpendicular magnetic anisotropy (PMA), which increases as a function of the thickness of the film. Density functional theory (DFT) as implemented in the Vienna Ab initio simulation package (VASP) is employed here to perform a comprehensive theoretical investigation of the structural, electronic and magnetic properties of the Mn2VIn(001) films of varying thickness. Our calculations were performed on fully relaxed structures, with five to seventeen mono layers (ML). The degree of spin polarization is higher in the (001) Mn2VIn thin films as compared to the bulk in contrast to what is usually the case and as in Mn2VAl, which is isoelectronic to Mn2VIn as well as inCo2VIn (001) films studied for comparison. Tetragonal distortions are found in all the systems after relaxation. The distortion in the Mn2VIn system persists even for the 17ML thin film, resulting in PMA in the Mn2VIn system. This significant finding has potential to contribute to spin transfer torque (STT) and magnetic random access memory MRAM applications, as materials with PMA derived from volume magnetocrystalline anisotropy are being proposed as ideal magnetic electrodes