Properties of Iron Atoms at Grain Boundaries in Fe and Fe72Al28

1998 ◽  
Vol 527 ◽  
Author(s):  
O. Schneeweiss ◽  
I. Turek ◽  
J. Čermák ◽  
P. Lejček
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Single Crystals ◽  
First Principles ◽  
Magnetic Moments ◽  
Emission Mössbauer Spectroscopy ◽  
First Principles Calculations ◽  
Hyperfine Parameters ◽  
Impurity Atoms ◽  
Atomic Spacing

ABSTRACTLocation of diffused 57Co atoms in single crystals, bicrystals and polycrystals of pure iron and Fe72Al28alloy were investigated by means of emission Mössbauer spectroscopy. To interpret the results, first principles calculations of iron atom magnetic moments and hyper-fine field were carried out. From comparison of M6ssbauer spectra of single crystals with those of bicrystals and polycrystals, an information about grain boundary positions occupied by diffusing atoms is obtained. It is shown that about 5% of the diffusing atoms at the {112} grain boundary of iron are located at the positions either having impurity atoms in the nearest neighbourhood or characterized by larger atomic spacing in comparison with the bulk. In the Fe72Al28 a dominating portion of diffusing atoms have different surrounding than in grain volume. An enrichment of grain boundaries by aluminum could explain their hyperfine parameters.

First-Principles Calculations of Stacking Faults and Grain Boundaries in Metals

1990 ◽  
Vol 213 ◽  
Author(s):  
K. Hampel ◽  
D.D. Vvedensky ◽  
S. Crampin
Keyword(s):  
Magnetic Properties ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
First Principles ◽  
Stacking Faults ◽  
First Principles Calculations ◽  
Comprehensive Description ◽  
Planar Defects ◽  
Detailed Understanding ◽  
Defect Energies

ABSTRACTA detailed understanding of planar defects plays an important role in the search for a comprehensive description of the mechanical behaviour of metals and alloys. We present calculations for isolated stacking faults and grain boundaries using the layer Korringa-Kohn-Rostoker method including an assessment of the force theorem, which has already proven itself in evaluating defect energies for elemental close-packed metals. These ab initio total energy calculations will be supplemented by a study of the changes in bonding and local magnetic properties near a symmetric Σ5 (310) grain boundary in Fe

scholarly journals The Electronic Structure of Grain Boundaries in NB

1990 ◽  
Vol 209 ◽  
Author(s):  
Erik C. Sowa ◽  
A. Gonis ◽  
X. -G. Zhang
Keyword(s):  
Electronic Structure ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Multiple Scattering ◽  
First Principles ◽  
Scattering Theory ◽  
Real Space ◽  
First Principles Calculations ◽  
Densities Of States ◽  
Local Densities

ABSTRACTWe present first-principles calculations of the electronic structure of Nb grain boundaries. These are the first such calculations for a bcc metal using the real-space multiple-scattering theory (RSMST). Local densities of states near a Σ5 twist grain boundary are compared to those for bulk Nb.

The formation of H bubbles at small-angle tilt grain boundaries in W films

2016 ◽  
Vol 18 (48) ◽  
pp. 33103-33108 ◽  
Author(s):  
Zhihai He ◽  
H. Y. He ◽  
R. Ding ◽  
B. C. Pan ◽  
J. L. Chen
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Small Angle ◽  
First Principles ◽  
First Principles Calculations ◽  
Tilt Grain Boundary

The accumulation of H at the small-angle tilt grain boundary (GB) in the W(001) surface is investigated, on the basis of the first-principles calculations.

First-Principles Studies on Grain Boundary Energies of [110] Tilt Grain Boundaries in Aluminum

2007 ◽  
Vol 561-565 ◽  
pp. 1837-1840 ◽  
Author(s):  
Y. Inoue ◽  
Tokuteru Uesugi ◽  
Yorinobu Takigawa ◽  
Kenji Higashi
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Atomic Structure ◽  
First Principles ◽  
Boundary Structure ◽  
First Principles Calculations ◽  
Atomic Structures ◽  
Grain Boundary Structure ◽  
Transmission Electron ◽  
Tilt Grain Boundary

The grain boundary structure and its energy are necessary for the fundamental understanding of the physical properties of materials. In aluminum, three distinct atomic structures of a Σ9(221)[110] tilt grain boundary have been reported in previous studies using atomistic simulations and a high-resolution transmission electron microscopy (HRTEM). In this work, we studied the atomic structure and energy of the Σ9 tilt grain boundary in aluminum using first-principles calculations. A comparison of the grain boundary energies among the three distinct Σ9 tilt grain boundaries determined through first-principles calculations allowed us to identify the most stable atomic structure of Σ9 tilt grain boundary in aluminum.

scholarly journals Spin Polarization Properties of Pentagonal PdSe2 Induced by 3D Transition-Metal Doping: First-Principles Calculations

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2339 ◽  
Author(s):  
Xiuwen Zhao ◽  
Bin Qiu ◽  
Guichao Hu ◽  
Weiwei Yue ◽  
Junfeng Ren ◽  
...  
Keyword(s):  
Transition Metal ◽  
Spin Polarization ◽  
First Principles ◽  
Magnetic Moments ◽  
First Principles Calculations ◽  
Density Distributions ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Theoretical Investigations ◽  
Densities Of States

The electronic structure and spin polarization properties of pentagonal structure PdSe2 doped with transition metal atoms are studied through first- principles calculations. The theoretical investigations show that the band gap of the PdSe2 monolayer decreases after introducing Cr, Mn, Fe and Co dopants. The projected densities of states show that p-d orbital couplings between the transition metal atoms and PdSe2 generate new spin nondegenerate states near the Fermi level which make the system spin polarized. The calculated magnetic moments, spin density distributions and charge transfer of the systems suggest that the spin polarization in Cr-doped PdSe2 will be the biggest. Our work shows that the properties of PdSe2 can be modified by doping transition metal atoms, which provides opportunity for the applications of PdSe2 in electronics and spintronics.

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.

STABLE STRUCTURES, ELECTRIC AND MAGNETIC PROPERTIES OF NANOPARTICLES COn(n = 1-6) CLUSTERS: FIRST-PRINCIPLES CALCULATIONS

2013 ◽  
Vol 27 (15) ◽  
pp. 1362007
Author(s):  
JUN LIU ◽  
SHENG-BIAO TAN ◽  
HUI-NING DONG
Keyword(s):  
Magnetic Properties ◽  
Ground State ◽  
First Principles ◽  
Lower Energy ◽  
Magnetic Moments ◽  
Molecular Orbitals ◽  
First Principles Calculations ◽  
Half Metallicity ◽  
Ground State Structures ◽  
Stable Structures

The ground state geometric structures of the nanoparticles or clusters CO n(n = 1-6) were given based on the first-principles calculations. Then the magnetic properties of the clusters CO n(n = 1-6) and ( CO n)-2(n = 1-6) were calculated in system. Results show that their ground state structures are closely related to the numbers of O-ions. These clusters have no magnetic moments and half-metallicity if they are electroneutral. However, they have magnetic moments if they have positive or negative charges. The total magnetic moments of the clusters ( CO n)-2(n = 1-6, but n≠3) are all 2.0000 μB, and all their ions have contributions to the total magnetic moments. The main reason is that the molecular orbitals with lower energy filled with paired electrons and the molecular orbitals with higher energy are occupied by two electrons in parallel.

Fast and scalable prediction of local energy at grain boundaries: machine-learning based modeling of first-principles calculations

2017 ◽  
Vol 25 (7) ◽  
pp. 075003 ◽  
Author(s):  
Tomoyuki Tamura ◽  
Masayuki Karasuyama ◽  
Ryo Kobayashi ◽  
Ryuichi Arakawa ◽  
Yoshinori Shiihara ◽  
...  
Keyword(s):  
Machine Learning ◽  
Grain Boundaries ◽  
First Principles ◽  
Local Energy ◽  
First Principles Calculations
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