Defect formation energy and magnetic properties of off-stoichiometric Ni-Mn-In alloys by first-principles calculations

2013 ◽  
Vol 113 (17) ◽  
pp. 174901 ◽  
Author(s):  
J. Bai ◽  
N. Xu ◽  
J.-M. Raulot ◽  
Y. D. Zhang ◽  
C. Esling ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
First Principles ◽  
Formation Energy ◽  
Defect Formation ◽  
First Principles Calculations ◽  
Defect Formation Energy

Nitrogen-induced magnetism in stannates from first-principles calculations

2016 ◽  
Vol 30 (32) ◽  
pp. 1650236
Author(s):  
Wen-Zhi Xiao ◽  
Bo Meng ◽  
Hai-Qing Xu ◽  
Qiao Chen ◽  
Ling-Ling Wang
Keyword(s):  
Magnetic Properties ◽  
Spin Polarization ◽  
First Principles ◽  
Short Range ◽  
Formation Energy ◽  
Spin Splitting ◽  
Coupling Mechanism ◽  
First Principles Calculations ◽  
Nitrogen Doped ◽  
Perovskite Type

First-principles calculations have been used to comparatively investigate electronic and magnetic properties of nitrogen-doped (N-doped) nonmagnetic semiconductor perovskite-type stannate (MSnO3, M = Ca, Sr, Ba). A total magnetic moment of 1.0 [Formula: see text] induced by N is found in MSnO3 supercell with one N dopant. The spontaneous polarization mainly originates from spin splitting on [Formula: see text] state of N. The medium-sized formation energy shows that the N-doped MSnO3 can be realized experimentally under the metal-rich environments, but the clustering tendency and short-range coupling imply that the stannate matrices are unsuitable for magnetizing by substituting N for O. Our study offers a fresh sight of spontaneous spin polarization in [Formula: see text] magnetism. The FM coupling in N-doped MSnO3 should be attributed to the hole-mediated [Formula: see text]–[Formula: see text] coupling mechanism.

Crystal Structure, Phase Stability and Magnetic Properties of Cu-Doped Ni2MnGa Alloys from First-Principles Calculations

2016 ◽  
Vol 873 ◽  
pp. 3-7
Author(s):  
Mei Jie Yang ◽  
Jing Bai ◽  
Ze Li ◽  
Teng Fei Qiu
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Phase Stability ◽  
First Principles ◽  
Formation Energy ◽  
Ferromagnetic State ◽  
First Principles Calculations ◽  
Ferromagnetic Shape Memory Alloys ◽  
Electronic Density ◽  
Structure Phase

The effects of Cu addition on the crystal structure, phase stability and magnetic properties of Ni8Mn4-xGa4Cux (x=0, 0.5, 1, 1.5 and 2) ferromagnetic shape memory alloys are systematically investigated by first-principles calculations. The formation energy results indicate that the added Cu preferentially occupies the Mn sites in Ni2MnGa alloy. The formation energy results indicate that ferromagnetic austenite is more stable than the paramagnetic one. The ferromagnetic state becomes instable and paramagnetic state becomes more stable when Mn is gradual substituted by Cu. Furthermore, the electronic density of states gives rise to the difference in the magnetic properties.

scholarly journals Defect formation energy and magnetic properties of aluminum-substituted M-type barium hexaferrite

2014 ◽  
Vol 1 ◽  
pp. 45-50 ◽  
Author(s):  
Amitava Moitra ◽  
Sungho Kim ◽  
Seong-Gon Kim ◽  
S.C. Erwin ◽  
Yang-Ki Hong ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Formation Energy ◽  
Defect Formation ◽  
Barium Hexaferrite ◽  
Defect Formation Energy

Defect formation of CuI-doped by group-IIB elements

2019 ◽  
Vol 33 (01) ◽  
pp. 1850423
Author(s):  
Hui Chen ◽  
Mu Gu
Keyword(s):  
First Principles ◽  
Formation Energy ◽  
Defect Formation ◽  
Valence Band Maximum ◽  
Acceptor Level ◽  
First Principles Calculations ◽  
Transition Energies ◽  
Band Maximum ◽  
P Type ◽  
Formation Energies

First-principles calculations have been performed to investigate the doping defects in CuI with group-IIB elements such as Zn, Cd and Hg. The calculated transition energies for substitutional Zn, Cd and Hg are 1.32, 1.28 and 0.60 eV, respectively. These group-IIB elements at the substitutional sites complex with a copper vacancy [Formula: see text] have the lower formation energies as compared to dopants located at the substitutional sites or interstitial sites, respectively. Among all the complex defects considered, [Formula: see text] has the lowest formation energy and it induces the acceptor level [Formula: see text] eV above the valence-band maximum (VBM), which is close to the acceptor level [Formula: see text] eV of [Formula: see text], suggesting that Hg may be a good dopant for CuI to improve its p-type conductivity.

scholarly journals First Principles Calculations of Defects in Unstable Crystals: Austenitic Iron

2011 ◽  
Vol 1363 ◽  
Author(s):  
G.J. Ackland ◽  
T.P.C. Klaver ◽  
D.J. Hepburn
Keyword(s):  
Point Defects ◽  
First Principles ◽  
Defect Formation ◽  
Single Layer ◽  
Temperature Limit ◽  
Reference State ◽  
First Principles Calculations ◽  
General Picture ◽  
Bcc Iron ◽  
Defect Energies

ABSTRACTFirst principles calculations have given a new insight into the energies of point defects in many different materials, information which cannot be readily obtained from experiment. Most such calculations are done at zero Kelvin, with the assumption that finite temperature effects on defect energies and barriers are small. In some materials, however, the stable crystal structure of interest is mechanically unstable at 0K. In such cases, alternate approaches are needed. Here we present results of first principles calculations of austenitic iron using the VASP code. We determine an appropriate reference state for collinear magnetism to be the antiferromagnetic (001) double-layer (AFM-d) which is both stable and lower in energy than other possible models for the low temperature limit of paramagnetic fcc iron. Another plausible reference state is the antiferromagnetic (001) single layer (AFM-1). We then consider the energetics of dissolving typical alloying impurities (Ni, Cr) in the materials, and their interaction with point defects typical of the irradiated environment. We show that the calculated defect formation energies have fairly high dependence on the reference state chosen: in some cases this is due to instability of the reference state, a problem which does not seem to apply to AFM-d and AFM-1. Furthermore, there is a correlation between local free volume magnetism and energetics. Despite this, a general picture emerge that point defects in austenitic iron have geometries similar to those in simpler, non-magnetic, thermodynamically stable FCC metals. The defect energies are similar to those in BCC iron. The effect of substitutional Ni and Cr on defect properties is weak, rarely more than tenths of eV, so it is unlikely that small amounts of Ni and Cr will have a significant effect on the radiation damage in austenitic iron at high temperatures.

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