Theoretical investigation of Fe–Rh binary nanoalloys: Chemical ordering and magnetic behavior

2022 ◽  
Author(s):  
Hüseyin Yıldırım
Keyword(s):  
Order Parameter ◽  
Bond Order ◽  
Density Functional ◽  
Energy Analysis ◽  
Magnetic Moments ◽  
Magnetic Behavior ◽  
Equatorial Region ◽  
Functional Theory ◽  
Mixing Energy ◽  
Chemical Ordering

Gupta and Density Functional Theory (DFT) calculations were performed to investigate of structural and magnetic behaviors of 19 atom FenRh[Formula: see text] ([Formula: see text]–19) nanoalloys. A double icosahedron structure was considered for FenRh[Formula: see text] ([Formula: see text]–19) nanoalloys. Significantly, the effects of Fe atom addition on the chemical ordering, stability and total magnetic moments of the nanoalloys were investigated. Local optimization results at the Gupta level show that the Fe atoms are located in the center of the double icosahedron structure and finally in the equatorial region on the surface. The mixing energy analysis obtained that Fe[Formula: see text]Rh7 and Fe4Rh[Formula: see text] nanoalloys are the most stable compositions at Gupta and DFT levels, respectively. It was found that FenRh[Formula: see text] ([Formula: see text]–19) nanoalloys are energetically suitable for mixing at both Gupta and DFT levels. Also, the bond order parameter result is compatible with the mixing energy analysis result. The total magnetic moments of the FenRh[Formula: see text] ([Formula: see text]–19) nanoalloys increase with the addition of the Fe atom, which is a ferromagnetic metal.

Investigation of structural and energetic behavior of 55-atom Pt–Ag–Au ternary nanoalloys

2021 ◽  
pp. 2150174
Author(s):  
Hüseyin Yıldırım ◽  
Ali Kemal Garip
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Energy Analysis ◽  
Many Body ◽  
Functional Theory ◽  
Mixing Energy ◽  
Chemical Ordering ◽  
The One ◽  
Body Potential ◽  
Basin Hopping

A systematic theoretical investigation of structural and energetic behaviors of 55-atom Pt–Ag–Au ternary nanoalloys has been performed in two different composition systems. We have performed Gupta and Density Functional Theory (DFT) approaches on chosen systems. The Basin-Hopping algorithm is used for structural optimizations of PtnAg[Formula: see text]Au[Formula: see text] ([Formula: see text]–13) and PtnAu[Formula: see text]Ag[Formula: see text] ([Formula: see text]–13) ternary nanoalloys with Gupta many-body potential to model interatomic interactions. Local optimization results show that while the tendency of Au atoms to be located varies according to the composition system, the tendency of Pt and Ag atoms to be located does not change in both. For all compositions of Pt–Ag–Au nanoalloys, the structures with the best chemical ordering were then reoptimized by DFT relaxations and the mixing energies of the Gupta and DFT levels were compared. Our mixing energy analysis showed that PtnAg[Formula: see text]Au[Formula: see text] ([Formula: see text]–13) nanoalloys are not energetically suitable for mixing at both Gupta and DFT level. Also, mixing energy variations of PtnAu[Formula: see text]Ag[Formula: see text] ([Formula: see text]–13) nanoalloys obtained at Gupta level does not agree with the one obtained at DFT level. In addition, it has been found that the minimization energy changes when an atom in the central site is exchanging by an atom in the second shell and surface.

Magnetism and Half-Metallicity in (100) Surface of Inverse Heusler Mn2CoSb

2014 ◽  
Vol 1015 ◽  
pp. 377-380
Author(s):  
Tao Chen ◽  
Ying Chen ◽  
Yin Zhou ◽  
Hong Chen
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
First Principles ◽  
Heusler Alloy ◽  
Density Functional ◽  
Magnetic Moments ◽  
Surface States ◽  
First Principles Calculations ◽  
Half Metallicity ◽  
Functional Theory

Using the first-principles calculations within density functional theory (DFT), we investigated the electronic and magnetic properties of (100) surface of inverse Heusler alloy Mn2CoSb with five different terminations. Our work reveals that the surface Mn atom moves to vacuum while surface Co atom moves to slab. Moreover, duo to the reason that the surface atom lost half of the nearest atoms with respect to the bulk phase, resulting in the decrease of hybridization, the atom-resolved spin magnetic moments of surface atoms are enhanced. Further investigation on DOS and PDOS showed that half-metallicity was preserved only in SbSb-termination while was destroyed in MnCo-, MnSb-, MnMn-, and CoCo-termination due to the appearance of surface states.

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.

scholarly journals Impact of Nano-Scale Distribution of Atoms on Electronic and Magnetic Properties of Phases in Fe-Al Nanocomposites: An Ab Initio Study

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1059 ◽  
Author(s):  
Ivana Miháliková ◽  
Martin Friák ◽  
Yvonna Jirásková ◽  
David Holec ◽  
Nikola Koutná ◽  
...  
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Nearest Neighbor ◽  
Magnetic Moments ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Α Phase ◽  
Ordered Intermetallic ◽  
Random Structures ◽  
The Impact

Quantum-mechanical calculations are applied to examine magnetic and electronic properties of phases appearing in binary Fe-Al-based nanocomposites. The calculations are carried out using the Vienna Ab-initio Simulation Package which implements density functional theory and generalized gradient approximation. The focus is on a disordered solid solution with 18.75 at. % Al in body-centered-cubic ferromagnetic iron, so-called α -phase, and an ordered intermetallic compound Fe 3 Al with the D0 3 structure. In order to reveal the impact of the actual atomic distribution in the disordered Fe-Al α -phase three different special quasi-random structures with or without the 1st and/or 2nd nearest-neighbor Al-Al pairs are used. According to our calculations, energy decreases when eliminating the 1st and 2nd nearest neighbor Al-Al pairs. On the other hand, the local magnetic moments of the Fe atoms decrease with Al concentration in the 1st coordination sphere and increase if the concentration of Al atoms increases in the 2nd one. Furthermore, when simulating Fe-Al/Fe 3 Al nanocomposites (superlattices), changes of local magnetic moments of the Fe atoms up to 0.5 μ B are predicted. These changes very sensitively depend on both the distribution of atoms and the crystallographic orientation of the interfaces.

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.

POSSIBLE Si-BASED HALF-METALLIC MATERIALS: MnSi46 CLATHRATES

2012 ◽  
Vol 26 (18) ◽  
pp. 1250114
Author(s):  
ZHI-WEI ZHAO ◽  
JING WANG ◽  
HUI-YAN ZHAO ◽  
YING LIU
Keyword(s):  
Density Functional ◽  
Magnetic Moments ◽  
Density Functional Theory Calculations ◽  
Metallic Materials ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Half Metallic ◽  
Silicon Clathrates ◽  
Ni Dopant ◽  
Center Site

The structural and magnetic properties of M Si 46 (M = Mn , Fe , Co and Ni ) clathrates have been studied using density functional theory calculations within the generalized gradient approximation. When the structures involve a dopant at the center of a Si 20 or Si 24 cage, the results show that the neighboring atoms around the dopant are drawn in toward the center. Some of the silicon clathrates with a Mn or Co dopant at the center site of a Si 20 cage, or a Mn , Fe or Ni dopant at the center site of a Si 24 cage are found to be half-metallic materials with large magnetic moments, and others with a Fe or Ni dopant at the center site of a Si 20 cage or a Co dopant at the center site of a Si 24 cage display semi-metallic characters. In particular, MnSi 46 with a half-metallic gap of 0.70 eV and a magnetic moment of 5.00 μ B shows promise for applications in the field of spintronics.

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 .

Vibrational spectra of alkylamino substituted phthalocyanine compounds: Density functional theory calculations

2018 ◽  
Vol 22 (09n10) ◽  
pp. 771-776 ◽  
Author(s):  
Xin Chen ◽  
Chiming Wang ◽  
Yuxiang Chen ◽  
Dongdong Qi ◽  
Jianzhuang Jiang
Keyword(s):  
Density Functional Theory ◽  
Infrared Spectra ◽  
Vibrational Spectra ◽  
Bond Order ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Molecular Orbitals ◽  
Functional Theory ◽  
Localized Molecular Orbitals ◽  
Theoretical Investigations

The infrared spectra of tetrakis(dibutylamino) phthalocyanine and octakis(dibutylamino) compounds were studied via theoretical investigations. The results reveal deep fusion of the peripheral alkylamino moieties with the phthalocyanine chromophore in the tetrakis(dibutylamino)- but not in the octakis(dibutylamino)-phthalocyanine compounds. The successive localized molecular orbitals (LMO) and bond order analyses give support for the infrared vibrational results.

AB INITIO STUDY OF STRUCTURAL STABILITY AND MAGNETIC PROPERTIES OF Con(n = 2 - 10): A STUDY BASED ON PSEUDOPOTENTIALS DFT

2011 ◽  
Vol 22 (04) ◽  
pp. 359-369
Author(s):  
M. SAMAH ◽  
B. MOULA
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Ground State ◽  
Density Functional ◽  
Magnetic Moments ◽  
Stability Study ◽  
Ab Initio Study ◽  
Functional Theory ◽  
The Stability ◽  
Magic Cluster

The lowest-energy geometric and isomers of freestanding Co n clusters (n = 2 - 10) and their corresponding magnetic moments have been studied using the Siesta code based on pseudopotential density-functional theory. The calculated results show that there are many isomers near the ground state. Different isomers hold different magnetic moment. The stability study shows that among the investigated clusters, the hexamer one is the most stable and is the magic cluster. Dissociation channels energy are also studied.

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