First-Principle Study on Half-Metallic Ferromagnetism and Structural Stability of C-Doped Alkaline-Earth Chalcogenides under Pressure

2014 ◽  
Vol 1052 ◽  
pp. 155-162
Author(s):  
Hui Zhao ◽  
Qian Han
Keyword(s):  
Density Of States ◽  
Density Functional ◽  
Magnetic Phase ◽  
Magnetic Moments ◽  
Second Order ◽  
Magnetic Phase Transitions ◽  
First Principle ◽  
Half Metallic ◽  
Lattice Constants ◽  
Cell Volumes

Three half-metallic ferromagnets with NaCl structure, X4CS3(X = Mg, Ca and Sr) are investigated by the first principle calculations based on the density functional theory in thegeneralized gradient approximation. Non-spin and spin polarized calculations are done to obtain the lattice constants, the equilibrium cell volumes, the stable energies and the magnetic moments of X4CS3, and band structure and density of states for X4CS3at high pressure are calculated. From the calculations it has been found that X4CS3is stable in the FM state. The corresponding lattice constants and the equilibrium cell volumes in FM are greater than that in NM. The magnetic moment of X4CS3decrease as pressure increases, and a second order magnetic phase transition of Sr4CS3from FM to NM state at pressure of 140GPa, but a second order magnetic phase transitions of Mg4CS3and Ca4CS3have not been found. According to the band and the density of states, as the pressure increases the half-metallic nature of X4CS3destroyed.

DFT study of elastic, half-metallic and optical properties of Co2V(Al, Ge, Ga and Si) compounds

2017 ◽  
Vol 31 (14) ◽  
pp. 1750109 ◽  
Author(s):  
Heidar Khosravi ◽  
Arash Boochani ◽  
Golnaz Rasolian ◽  
Shahram Solaymani ◽  
Sirvan Naderi
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Magnetic Moments ◽  
Elastic Stability ◽  
Metallic Behavior ◽  
Functional Theory ◽  
Spin Mode ◽  
Half Metallic ◽  
Lattice Constants ◽  
Optical Treatment

First-principles study of elastic, electronic and optical properties of full-Heusler Co2V(Al, Ge, Ga and Si) compounds are calculated through density functional theory (DFT) to obtain and compare the mentioned properties. Equilibrium lattice constants of these compounds are in good agreement with other works. Electronic calculations are shown full spin polarization at Fermi level for all compounds, so in the down spin, indirect bandgap is calculated as 0.33, 0.6, 0.2 and 0.8 eV for Co2V(Al, Ge, Ga and Si), respectively. The integer amounts of the magnetic moments are compatible with Slater–Pauling role. The optical treatment of Co2VGa is different from three other compounds. All mentioned compounds have metallic behavior by 22 eV plasmonic frequency. The imaginary part of the dielectric function for the up spin indicates that the main optical transitions occurred in this spin mode. Moreover, the elastic results show that the Co2VGa does not have elastic stability, but the other three compounds have fully elastic stability and the Co2V(Al, Ge and Si) belong to the hardness of materials.

Tunable Magnetism and Half-Metallic Stability in Si-Doped Hg2CuTi-Type Ti2CoGa Alloy

2012 ◽  
Vol 229-231 ◽  
pp. 130-133 ◽  
Author(s):  
Bo Wu ◽  
Yu Feng ◽  
Hong Kuan Yuan ◽  
Hong Chen
Keyword(s):  
Density Functional ◽  
Magnetic Moments ◽  
Half Metallicity ◽  
Functional Theory ◽  
Half Metallic ◽  
Lattice Constants ◽  
Indirect Exchange ◽  
The Density Functional Theory ◽  
Si Doped ◽  
Direct Hybridization

Using the ab-initio calculations within the density functional theory (DFT), we have investigated the electronic structure, magnetism and half-metallic stability of Si-doped Heusler compound Ti2CoGa with Hg2CuTi-type structure. The results revel that the lattice constants and total magnetic moments in per unit obey the Vegard’s rule and the Slater-Pauling rule well, respectively. The most stable half-metallicity occurs at doping concentration x=0.75 because the Fermi level is located at the middle of the spin-minority gap. Our studies also indicate that the competition between RKKY-type indirect exchange and direct hybridization of d-electronic atoms plays a dominating role in determining the magnetism.

scholarly journals Prediction of electronic and half metallic properties of Mn2YSn (Y = Mo, Nb, Zr) Heusler alloys

2021 ◽  
Vol 24 (1) ◽  
pp. 13703
Author(s):  
S. Zeffane ◽  
M. Sayah ◽  
F. Dahmane ◽  
M. Mokhtari ◽  
L. Zekri ◽  
...  
Keyword(s):  
Density Functional ◽  
Magnetic Moments ◽  
Heusler Alloys ◽  
Type Structure ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Half Metallic ◽  
Spintronic Devices ◽  
Lattice Constants ◽  
Good Agreement

We investigate the structural, electronic and magnetic properties of the full Heusler compounds Mn2YSn (Y = Mo, Nb, Zr) by first- principles density functional theory using the generalized gradient approximation. It is found that the calculated lattice constants are in good agreement with the theoretical values. We observe that the Cu2MnAl-type structure is more stable than the Hg2CuTi type. The calculated total magnetic moments of Mn2NbSn and Mn2ZrSn are 1 μB and 2 μB at the equilibrium lattice constant of 6.18 Å and 6.31 Å, respectively, for the Cu2MnAl-type structure. Mn2MoSn have a metallic character in both Hg2CuTi and Cu2MnAl type structures. The total spin magnetic moment obeys the Slater-Pauling rule. Half-metal exhibits 100% spin polarization at the Fermi level. Thus, these alloys are promising magnetic candidates in spintronic devices.

First-Principle Calculations for Magnetism of Mn-Doped Graphene

2013 ◽  
Vol 709 ◽  
pp. 184-187 ◽  
Author(s):  
Jia Jia Liu ◽  
Tian Min Lei ◽  
Yu Ming Zhang ◽  
Pei Ting Ma ◽  
Zhi Yong Zhang
Keyword(s):  
Density Of States ◽  
Magnetic Moment ◽  
Density Functional ◽  
Magnetic Semiconductors ◽  
Magnetic Moments ◽  
Dilute Magnetic Semiconductors ◽  
First Principle ◽  
First Principle Calculation ◽  
Doped Graphene ◽  
Mn Doped

Mn doped graphene-based dilute magnetic semiconductors (DMS) are investigated using the first-principle calculation based on density functional theory. In this paper, the Mn-C bond length, formation energy and magnetic moment are calculated in different doping systems and their density of states is made a detailed analysis. It is found that Mn-doped graphene has strong ferromagnetic properties and the magnetic moments of graphene supercells are different with the impurity concentrations. These supercells of a Mn atom substituting a C atom are increasingly stable with extending cells and the 11×11 supercell possesses the biggest magnetic moment of 3.8μB in these systems. The analysis of the density of states indicates the magnetic properties of Mn-doped graphene derive from the p-d exchange mechanism.

Tunable Magnetism and Half-Metallic Stability of Half-Heusler Compound NiMn1-xNbxSb

2011 ◽  
Vol 415-417 ◽  
pp. 1407-1410
Author(s):  
Qing Zhou ◽  
Bo Wu ◽  
Hong Kuan Yuan ◽  
Hong Chen
Keyword(s):  
Density Functional ◽  
Magnetic Moments ◽  
Magnetic Coupling ◽  
First Principles Calculations ◽  
Half Metallicity ◽  
Functional Theory ◽  
Half Metallic ◽  
Heusler Compound ◽  
Lattice Constants ◽  
The Density Functional Theory

By using the first-principles calculations within the density functional theory (DFT), we investigate the electronic structure, magnetism and half-metallic stability of half-Heusler compound NiMn1-xNbxSb. The results showed that the lattice constants and magnetic moments per unit respectively follow the Vegard law and the Slater-Pauling rule well. The most stable half-metallicity occurs at doping concentration x=0.25 due to the Fermi level is situated the middle of the spin-down gap. Our studies also indicate that the competition of hybridization of d-electrons and RKKY-type magnetic coupling plays a dominating role in determining the magnetism.

Electronic Structure and Magnetic Properties of Ga-Doped Heusler Alloy Co2FeSi

2011 ◽  
Vol 130-134 ◽  
pp. 1430-1434 ◽  
Author(s):  
Yu Feng ◽  
Bo Wu ◽  
Hong Kuan Yuan ◽  
Hong Chen
Keyword(s):  
Electronic Structure ◽  
Density Functional ◽  
Doping Concentration ◽  
Magnetic Moments ◽  
Half Metallicity ◽  
Functional Theory ◽  
Half Metallic ◽  
Heusler Compound ◽  
Lattice Constants ◽  
The Density Functional Theory

Using GGA+U (UCo=2.1eV, UFe=2.5eV) scheme based on the density functional theory (DFT), we investigate the electronic structure, magnetism and half-metallic stability of Ga-doped Heusler compound Co2FeSi. We find that the lattice constants and total magnetic moments in per unit respectively obey the Vegard’s rule and the Slater-Pauling rule well. The most stable half-metallicity occurs at doping concentration x=0.5 due to the Fermi level is situated slightly above the middle of the spin-down gap. Our studies also indicate that the RKKY-type exchange mechanism plays a dominating role in determining the magnetism of HMFs.

Magnetic Volume Effect of Hydrogen Diffusion in Palladium

2020 ◽  
Vol 310 ◽  
pp. 29-33
Author(s):  
Sarantuya Nasantogtokh ◽  
Xin Cui ◽  
Zhi Ping Wang
Keyword(s):  
Transition Metal ◽  
Density Of States ◽  
Density Functional ◽  
Hydrogen Diffusion ◽  
Magnetic Moments ◽  
Interstitial Site ◽  
Volume Effect ◽  
Face Centered Cubic ◽  
Hydrogen Atoms ◽  
Octahedral Interstitial Site

The electronic and magnetic properties of palladium hydrogen are investigated using first-principles spin-polarized density functional theory. By studying the magnetic moments and electronic structures of hydrogen atoms diffusing in face-centered cubic structure of transition metal Pd, we found that the results of magnetic moments are exactly the same in the two direct octahedral interstitial site-octahedral interstitial site diffusion paths-i.e. the magnetic moments are the largest in the octahedral interstitial site, and the magnetic moments are the lowest in saddle point positions. We also studied on the density of states of some special points, with the result that the density of states near the Fermi level is mainly contributed by 4d electrons of Pd and the change of magnetic moments with the cell volume in the unit cell of transition metal Pd with a hydrogen atom.

scholarly journals Spin Gapless Semiconductor–Nonmagnetic Semiconductor Transitions in Fe-Doped Ti2CoSi: First-Principle Calculations

2018 ◽  
Vol 8 (11) ◽  
pp. 2200 ◽  
Author(s):  
Yu Feng ◽  
Zhou Cui ◽  
Ming-sheng Wei ◽  
Bo Wu ◽  
Sikander Azam
Keyword(s):  
Magnetic Moment ◽  
Electronic Structures ◽  
Magnetic Moments ◽  
Total Magnetic Moment ◽  
First Principle ◽  
Half Metallic ◽  
Heusler Compound ◽  
First Principle Calculations ◽  
Metallic Ferromagnet

Employing first-principle calculations, we investigated the influence of the impurity, Fe atom, on magnetism and electronic structures of Heusler compound Ti2CoSi, which is a spin gapless semiconductor (SGS). When the impurity, Fe atom, intervened, Ti2CoSi lost its SGS property. As TiA atoms (which locate at (0, 0, 0) site) are completely occupied by Fe, the compound converts to half-metallic ferromagnet (HMF) TiFeCoSi. During this SGS→HMF transition, the total magnetic moment linearly decreases as Fe concentration increases, following the Slate–Pauling rule well. When all Co atoms are substituted by Fe, the compound converts to nonmagnetic semiconductor Fe2TiSi. During this HMF→nonmagnetic semiconductor transition, when Fe concentration y ranges from y = 0.125 to y = 0.625, the magnetic moment of Fe atom is positive and linearly decreases, while those of impurity Fe and TiB (which locate at (0.25, 0.25, 0.25) site) are negative and linearly increase. When the impurity Fe concentration reaches up to y = 1, the magnetic moments of Ti, Fe, and Si return to zero, and the compound is a nonmagnetic semiconductor.

Half-metallic properties in Co2XSn (X = Ti, V and Cr) full-Heusler compound

2019 ◽  
Vol 34 (02) ◽  
pp. 2050028 ◽  
Author(s):  
H. Abbassa ◽  
A. Labdelli ◽  
S. Meskine ◽  
Y. Benaissa Cherif ◽  
A. Boukortt
Keyword(s):  
Magnetic Moment ◽  
Density Functional ◽  
Heusler Alloys ◽  
Electronic Band ◽  
Half Metallic ◽  
Lattice Constants ◽  
Half Metal ◽  
Wide Range ◽  
Metallic Ferromagnetism ◽  
Half Metallic Ferromagnetism

First-principles calculations based on density functional theory (DFT) confirm the half-metallic ferromagnetism in both [Formula: see text] and [Formula: see text], and the nearly half-metallic ferromagnetism in [Formula: see text] Heusler alloys with the [Formula: see text]-type structure [Formula: see text]. The electronic band structures and density of states (DOS) calculations of the [Formula: see text] and [Formula: see text] compounds show that the spin-up electrons are metallic, whereas the spin-down bands are semiconducting with a gap of 0.47 eV and 0.53 eV, respectively, with 0.21 eV and 0.36 eV as a spin-flip gap, respectively. The [Formula: see text] and [Formula: see text] Heusler were half-metal compounds with magnetic moment of [Formula: see text] and [Formula: see text] at the equilibrium lattice constants [Formula: see text] Å and [Formula: see text] Å, respectively, which agrees with the Slater–Pauling rule, and have 100% polarization for a wide range of lattice parameters. The [Formula: see text] is a nearly half-metal (NHF) compound with magnetic moment of [Formula: see text] and 92.9% polarization at the equilibrium lattice constants [Formula: see text] Å and acquire half-metal behavior under the pressure 16.70 GPa.

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