Magnetism and magnetic anisotropy in UGa2

MRS Advances ◽  
2020 ◽  
Vol 5 (51) ◽  
pp. 2639-2645
Author(s):  
Banhi Chatterjee ◽  
Jindřich Kolorenč
Keyword(s):  
Density Functional ◽  
Magnetocrystalline Anisotropy ◽  
Magnetic Moments ◽  
Mean Field ◽  
Field Approximation ◽  
Theoretical Description ◽  
Mean Field Approximation ◽  
Functional Theory ◽  
Hubbard Interaction ◽  
The Density Functional Theory

AbstractWe investigate whether first-principles calculations with an improved description of electronic correlations can explain the large magnetic moments and the strong magnetocrystalline anisotropy in the ferromagnetic compound UGa2. The correlations are treated within a static mean-field approximation DFT+U combining the density functional theory (DFT) with an onsite Hubbard interaction U. We find that DFT+U improves the agreement of the magnetic moments with the experiment compared to DFT but worsens the theoretical description of the magnetocrystalline anisotropy.

Investigation on Mo-doped SnO2 for potential use in magnetoelectronic applications: The DFT framework

2020 ◽  
Vol 34 (05) ◽  
pp. 2050020
Author(s):  
Younes Ziat ◽  
Maryama Hammi ◽  
Zakaryaa Zarhri ◽  
Charaf Laghlimi ◽  
Rachid Bouachraoui ◽  
...  
Keyword(s):  
Density Functional ◽  
Diluted Magnetic Semiconductors ◽  
Magnetic Semiconductors ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Present System ◽  
The Density Functional Theory ◽  
Spin Polarized ◽  
Diluted Magnetic

The goal of this paper is to study the effect of the small amount of molybdenum-doped [Formula: see text] on the magnetism behavior of that system. We utilized the density functional theory (DFT): DFT framework within MACHIKANEYAMA2002V09 package based on Coherent Potential Approximation (CPA). Inducing the magnetism in the diluted magnetic semiconductors (DMS) with a low dopant concentration at adequate room-temperature is a challenge, so, we restricted the Mo impurity at 2%. In addition, the small amount of Mo-doped [Formula: see text] is found optimal in many studies related to other fields. The ferromagnetic stability is observed in [Formula: see text] system, since the [Formula: see text] state of Mo element is found around the Fermi level and is 100% spin polarized, the half-metallic characteristic is useful in magnetoelectronic applications. Within the mean-field approximation (MFA) we predict the Curie temperature, as an obtained value, the [Formula: see text] K, consequently, the present system showed potential promise for real applications.

scholarly journals Multimodels computation for adsorption capacity of activated carbon

2017 ◽  
Vol 36 (1-2) ◽  
pp. 508-520 ◽  
Author(s):  
Guodong Wang ◽  
Yun Tian ◽  
Jianchun Jiang ◽  
Jianzhong Wu
Keyword(s):  
Density Functional Theory ◽  
Activated Carbon ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Density Functional ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Functional Theory

The pore size distribution of activated carbon is conventionally characterized with nitrogen adsorption measurements at 77 K. The adsorption isotherms are commonly analyzed with a nonlocal density functional theory in combination with a mathematical model for the pore size and geometry. While nonlocal density functional theory is significantly more accurate than the Brunauer–Emmett–Teller theory for gas adsorption, its application to materials characterization is mostly based on a mean-field approximation for van der Waals attractions that is only qualitative in comparison with alternative versions of nonlocal density functional theory or molecular simulations. Toward development of a more reliable theoretical procedure, we compare mean-field approximation-nonlocal density functional theory with three recent versions of non-mean-field methods for gas adsorption at conditions corresponding to experiments for porous materials characterization. The potential applicability of different nonlocal density functional theory methods for pore size distribution predictions is evaluated in terms of the theoretical error bound scale analysis. We find that the weight density approximation is the most reliable for predicting the pore size distribution of amorphous porous materials. In addition to accurate isotherm, weight density approximation yields the theoretical error bound scale for pore size distribution prediction nearly 104 times narrower than that corresponding to mean-field approximation. The new theoretical procedure has been used to analyze the pore size distribution of four activated carbon samples and to predict the adsorption capacities of these materials.

The Determination of the Magnetoelectric Coupling Coefficient in Ferroelectric–Ferromagnetic Composite Based on PZT–Ferrite

2013 ◽  
Vol 58 (4) ◽  
pp. 1401-1403 ◽  
Author(s):  
J.A. Bartkowska ◽  
R. Zachariasz ◽  
D. Bochenek ◽  
J. Ilczuk
Keyword(s):  
Dielectric Permittivity ◽  
Coupling Coefficient ◽  
Mean Field ◽  
Field Approximation ◽  
Theoretical Description ◽  
Magnetoelectric Coupling ◽  
Mean Field Approximation ◽  
Dielectric Measurements ◽  
Temperature Dependences ◽  
Multiferroic Composite

Abstract In the present work, the magnetoelectric coupling coefficient, from the temperature dependences of the dielectric permittivity for the multiferroic composite was determined. The research material was ferroelectric-ferromagnetic composite on the based PZT and ferrite. We investigated the temperature dependences of the dielectric permittivity (") for the different frequency of measurement’s field. From the dielectric measurements we determined the temperature of phase transition from ferroelectric to paraelectric phase. For the theoretical description of the temperature dependence of the dielectric constant, the Hamiltonian of Alcantara, Gehring and Janssen was used. To investigate the dielectric properties of the multiferroic composite this Hamiltonian was expressed under the mean-field approximation. Based on dielectric measurements and theoretical considerations, the values of the magnetoelectric coupling coefficient were specified.

STRUCTURE AND MAGNETIC PROPERTIES OF Co12X(X = Ni, Ag, Pt, Au) CLUSTERS

2007 ◽  
Vol 21 (30) ◽  
pp. 5091-5098 ◽  
Author(s):  
Q. L. LU ◽  
J. C. JIANG ◽  
J. G. WAN ◽  
G. H. WANG
Keyword(s):  
Density Functional ◽  
Magnetic Moments ◽  
Stable Configuration ◽  
Many Body ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Au Clusters ◽  
The Density Functional Theory ◽  
Ground State Structures ◽  
Body Potential

The ground state structures of Co 12 X ( X = Ni , Ag , Pt , Au ) clusters are obtained by a genetic algorithm with a Gupta-like many-body potential, and further optimized using the density functional theory with generalized gradient approximation. The structures of Co 12 X have a slightly distorted icosahedral pattern. The X atom is on the surface for the most stable configuration. Their total magnetic moments are 0μ B , 3μ B , 21μ B , and 22μ B , respectively. The reasons for the reduction of magnetism of Co 12 X are discussed in detail.

MAGNETIC MAP OF MnNi ALLOYED MONOLAYER ON Cu(001) SUBSTRATE: AB-INITIO CALCULATIONS

2010 ◽  
Vol 09 (06) ◽  
pp. 619-622
Author(s):  
BOTHINA A. HAMAD
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Magnetic Moments ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Generalized Gradient Approximation ◽  
Exchange Correlation Potential ◽  
The Density Functional Theory ◽  
Correlation Potential

In this work, a theoretical study of the structural, electronic and magnetic properties are presented for Mn 0.5 Ni 0.5 alloyed overlayer adsorbed on Cu (001) surface. The calculations were performed using the density functional theory (DFT) and the exchange-correlation potential was treated by the generalized gradient approximation (GGA). The system was fully relaxed except for the central layer, which yields to outward relaxations and inward Mn and Ni surface atoms, respectively in the ferromagnetic and antiferromagnetic configurations. The in-plane ferromagnetic configuration was found to be more stable than the antiferromagnetic one by 25 meV/atom. The local magnetic moments of Mn atoms were found to be about 4 μ B , whereas those of the Ni atoms where found to be 0.46 μ B .

QUASILOCAL DENSITY FUNCTIONAL THEORY FOR NUCLEI INCLUDING PAIRING CORRELATIONS

2007 ◽  
Vol 16 (02) ◽  
pp. 249-262 ◽  
Author(s):  
X. VIÑAS ◽  
V. I. TSELYAEV ◽  
V. B. SOUBBOTIN ◽  
S. KREWALD
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Equations Of Motion ◽  
Mean Field ◽  
Field Operator ◽  
Functional Theory ◽  
Hartree Fock ◽  
Orbit Potential ◽  
The Density Functional Theory ◽  
Pairing Correlations

We propose first a generalization of the Density Functional Theory leading to single-particle equations of motion with a quasilocal mean-field operator containing a position-dependent effective mass and a spin-orbit potential. Ground-state properties of doubly magic nuclei are obtained within this framework using the Gogny D1S force and compared with the exact Hartree-Fock values. Next, extend the Density Functional Theory to include pairing correlations without formal violation of the particle-number condition. This theory, which is nonlocal, is simplified by a suitable quasilocal reduction. Some calculations to show the ability of this theory are presented.

Metal-Oxygen Hybridization and Core-Level Spectra in Actinide and Rare-Earth Oxides

MRS Advances ◽  
2016 ◽  
Vol 1 (44) ◽  
pp. 3007-3012 ◽  
Author(s):  
Jindřich Kolorenč
Keyword(s):  
Rare Earth ◽  
Density Functional ◽  
Mean Field Theory ◽  
Mean Field ◽  
Core Level ◽  
Dynamical Mean Field Theory ◽  
Functional Theory ◽  
The Core ◽  
The Density Functional Theory ◽  
Rare Earth Sesquioxides

ABSTRACT We employ a combination of the density-functional theory and the dynamical mean-field theory to study the electronic structure of selected rare-earth sesquioxides and dioxides. We concentrate on the core-level photoemission spectra, in particular, we illustrate how these spectra reflect the integer or fractional filling of the 4f orbitals. We compare the results to our earlier calculations of actinide dioxides and analyze why the core-level spectra of actinide compounds display a substantially reduced sensitivity to the filling of the 5f orbitals.

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.

Sign in / Sign up

Export Citation Format

Share Document