Vivek Kumar Jain

Electronic structure and magnetic properties of disordered Co2FeAl Heusler alloy

The effects of disorder on the magnetic properties of Co2FeAl alloy are reported. X-ray diffraction exhibit A2-type disordered structure. Room temperature Mossbauer studies show the presence of two sextets with hyperfine field values of 31T and 30T along with a nonmagnetic singlet. The electronic structure of ordered and disordered Co2FeAl alloys, investigated by means of the KKR Greens-function method shows that the magnetic moment of the ordered structure is 5.08μB and is 5.10μB when disordered. However, a much higher magnetic moment of 5.74μB is observed experimentally.

Ab initio study of Fe2MnZ (Al, Si, Ge) Heusler alloy using GGA approximation

Density functional theory based on FP-LAPW method used to investigate the electronic structure of Fe2MnZ, shows that the total spin magnetic moment shows a trend consistent with the Slater–Pauling curve. The Fe and Mn magnetic moment depend on choice of Z element although the magnetic moment of Z element is negative and less than 0.1 μB. Spin polarization calculations evidence 100% spin polarization for Fe2MnSi. Fe2MnAl and Fe2MnGe show metallic behavior with 93%, 98% spin polarization.

High energy ball milling study of Fe2MnSn Heusler alloy

The structural and magnetic properties of as-melted and high energy ball milled alloy samples have been studied by X-ray diffraction, DC magnetization and electronic structure calculations by means of density functional theory. The observed properties are compared to that of the bulk sample. There is a very good enhancement of saturation magnetization and coercivity in the nano-sized samples as compared to bulk which is explained in terms of structural disordering and size effect.

Structural and magnetic properties of high energy Ball milled Co2FeAl0.5Si0.5 Heusler alloy

Co2FeAl0.5Si0.5 Heusler alloy were prepared by argon arc meting and high energy ball milling technique has been used to investigate effect of reduction of grain size on structure and magnetic properties. X-ray diffraction analysis reveal that asmelted and all milled samples are single phased with A2 type disordered structure. On milling, saturation magnetization decreases and the value of coercivity increases. Electronic structure calculations show that the Co2FeAl0.5Si0.5 alloy is metallic with magnetic moment of 5.43 μB for ordered structure.Co2FeAl0.5Si0.5 Heusler alloy were prepared by argon arc meting and high energy ball milling technique has been used to investigate effect of reduction of grain size on structure and magnetic properties. X-ray diffraction analysis reveal that asmelted and all milled samples are single phased with A2 type disordered structure. On milling, saturation magnetization decreases and the value of coercivity increases. Electronic structure calculations show that the Co2FeAl0.5Si0.5 alloy is metallic with magnetic moment of 5.43 μB for ordered structure.

Study of the electronic structure properties in Co2NbIn/Sn Heusler alloys

Structural, electronic and magnetic properties of full-Heusler Co2NbIn and Co2NbSn compounds using density functional theory (DFT) have been studied. Lattice parameters obtained by volume optimization are 6.175A and 6179A for Co2NbIn and Co2NbSn respectively. Results suggest that Co2NbIn to be a half-metallic material with a gap of 0.58 eV at the Fermi level in the minority states while Co2NbSn has ferromagnetic behavior. The calculated magnetic moments are 2.00μB, 1.97μB for Co2NbIn and Co2NbSn. Formation energy and elastic parameters results suggest that both are energetically and elastically stable.Structural, electronic and magnetic properties of full-Heusler Co2NbIn and Co2NbSn compounds using density functional theory (DFT) have been studied. Lattice parameters obtained by volume optimization are 6.175A and 6179A for Co2NbIn and Co2NbSn respectively. Results suggest that Co2NbIn to be a half-metallic material with a gap of 0.58 eV at the Fermi level in the minority states while Co2NbSn has ferromagnetic behavior. The calculated magnetic moments are 2.00μB, 1.97μB for Co2NbIn and Co2NbSn. Formation energy and elastic parameters results suggest that both are energetically and elastically stable.

First principle calculation of half metallicity in Ti2MnSb Heusler alloy

Electronic structure and magnetic properties of Ti2MnSb Heusler alloy were computed using density functional theory implemented in WIEN2k code. The calculated magnetic moment at equilibrium lattice constant 6.33A was 2μB. Ti2MnSb shows a half metallic ferrimagnetic behavior with 0.77eV gap in the minority spin.

First principle calculation in FeCo overlayer on GaAs substrate

In this work the first principle electronic structure calculation is reported for FeCo/GaAs thin film system to investigate the effect of orientation on the electronic structural properties. A unit cell describing FeCo layers and GaAs layers is constructed for (100), (110), (111) orientation with vacuum of 30A to reduce dimensions. It is found that although the (110) orientation is energetically more favorable than others, the magnetic moment is quite large in (100) and (111) system compared to the (110) and is due to the total DOS variation with orientation