First-Principles Calculation of the Orbital Magnetic Moment of O and Cr in Half-metallic CrO2

2002 ◽  
Vol 718 ◽  
Author(s):  
Horng-Tay Jeng ◽  
G. Y. Guo
Keyword(s):  
Magnetic Moment ◽  
Magnetic Circular Dichroism ◽  
First Principles Calculation ◽  
Orbital Method ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
Orbital Moment ◽  
Half Metallic ◽  
Orbital Magnetic Moment ◽  
Good Agreement

AbstractThe electronic and magnetic properties of half-metallic CrO2 have been studied by using the full-potential linearized muffin-tin orbital method within the local spin-density approximation (LSDA)+U approach. It is found that the orbital magnetic moment of Cr atom is quenched while O atom exhibit relatively significant orbital moment in CrO2. For the Hubbard U of 3 eV, LSDA+U gives the orbital moment of -0.051μB/atom for Cr and -0.0025μB/atom for O, being in good agreement with the experimental orbital moments of -0.05 for Cr and -0.003μB/atom for O, respectively. In contrast, LSDA gives the orbital moment of -0.037 for Cr and -0.0011 μB/atom for O, being too small as compared with the magnetic circular dichroism measurements. For the larger U considered in this work, both spin and orbital moments almost increase linearly with respect to U.

Half-metallic ferromagnetism in V-doped ZnTe semiconductor at reduced dopant concentration

2014 ◽  
Vol 28 (13) ◽  
pp. 1450104 ◽  
Author(s):  
M. Sajjad ◽  
H. X. Zhang ◽  
N. A. Noor ◽  
S. M. Alay-e-Abbas ◽  
M. Abid ◽  
...  
Keyword(s):  
Density Functional ◽  
Spin Exchange ◽  
Density Functional Theory Calculations ◽  
Orbital Method ◽  
Ferromagnetic Behavior ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
Generalized Gradient ◽  
Half Metallic ◽  
Bonding Properties

In this study, we examine the structural, electronic, magnetic and bonding properties of zincblende phase Zn 1-x V x Te (x = 0.0625, 0.125, 0.25) compounds to present them as suitable candidates for spintronic applications. Density functional theory calculations have been used by implementing the accurate full-potential linear-augmented-planewave plus local-orbital method. Structural properties have been computed using Wu–Cohen generalized gradient approximation, whereas the modified Becke and Johnson local (spin) density approximation (mBJLDA) function has been employed for the evaluating ground state electronic properties and ferromagnetic behavior. The half-metallic (HM) ferromagnetism in Zn 1-x V x Te is analyzed in terms of V -3d states and it is shown that mBJLDA predicts wide HM gaps which promise the possibility of achieving V -doped ZnTe with high Curie temperature. The spin exchange splittings Δx(d) and Δx(pd) have been estimated and the contribution of conduction band (CB) and valence band (VB) in exchange splitting is calculated in terms of the exchange constants N0α and N0β. Furthermore, spin-polarized charge density calculation is presented for elucidating the bonding nature, while pressure dependence of total magnetic moment for three concentrations of V -doped ZnTe is also discussed.

ELASTIC PROPERTIES OF STRAINED FCC AND HCP IRON

1993 ◽  
Vol 07 (01n03) ◽  
pp. 207-211
Author(s):  
T. KRAFT ◽  
M. METHFESSEL ◽  
M. VAN SCHILFGAARDE ◽  
M. SCHEFFLER
Keyword(s):  
Energy Cost ◽  
Interplanar Distance ◽  
Orbital Method ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
Nearest Neighbour ◽  
Density Approximation ◽  
Neighbour Distance ◽  
Large Lattice ◽  
Fcc Phase

Using the full-potential linear muffin-tin orbital method within the local spin-density approximation we analyse the influence of the nearest neighbour distance on fcc(111) or hcp(0001) iron layers. The LDA-LSDA error in describing ferromagnetic phases is determined to be at least 15 mRy/atom. As a consequence of this error, our calculations favour paramagnetic ground states. In this sense, the reported results have some model character. However, our analysis of the elastic energy cost under distortions should hold for transition metals in general. Allowing relaxations of the interplanar distance the fcc phase can become energetically favourable over the hcp phase at large lattice mismatches. The main reason for this behaviour is the enhanced stiffness of the hcp interplanar bonds due to the shortening of the axial c/a ratio.

Ferrimagnetic Half-Metallicity of the New Quaternary Heusler Alloy CoCrScIn: FP-LAPW Method

SPIN ◽  
2021 ◽  
Vol 11 (02) ◽  
pp. 2150017
Author(s):  
Halima Hamada ◽  
Keltouma Boudia ◽  
Friha Khelfaoui ◽  
Kadda Amara ◽  
Toufik Nouri ◽  
...  
Keyword(s):  
Magnetic Moment ◽  
Density Functional ◽  
Structural Parameters ◽  
Magnetic Transition ◽  
Plane Waves ◽  
Full Potential ◽  
Half Metallicity ◽  
Metallic Behavior ◽  
Magnetic Transition Temperature ◽  
Half Metallic

The structural, electronic, elastic and magnetic properties of CoCrScIn were investigated using first principle calculations with applying the full-potential linearized augmented plane waves (FP-LAPW) method, based totally on the density functional theory (DFT). After evaluating the results, the calculated structural parameters reveal that CoCrScIn compound is stable in its ferrimagnetic configuration of the type-III structure. The mechanical properties show its brittle and stiffer behavior. The formation energy value showed that CoCrScIn can be experimentally synthesized. Additionally, the obtained band structures and density of states (DOS) reflect the half-metallic behavior of CoCrScIn, with an indirect bandgap of 0.43[Formula: see text]eV. The total magnetic moment of 3[Formula: see text][Formula: see text] and half-metallic ferrimagnetic state are maintained in the range 5.73–6,79 Å. The magnetic moment especially issues from the Cr-[Formula: see text] and Co-[Formula: see text] spin-polarizations. Furthermore, the calculations of Curie temperature reveal that CoCrScIn has high magnetic transition temperature of 836.7[Formula: see text]K.

MCD STUDIES IN 2p AND 3d XAS OF La1-xSrxCoO3

2002 ◽  
Vol 09 (02) ◽  
pp. 855-859
Author(s):  
MASAICHIRO MIZUMAKI ◽  
KENJI YOSHII ◽  
NAOMI KAWAMURA ◽  
MAKOTO NAKAZAWA
Keyword(s):  
Circular Dichroism ◽  
Magnetic Moment ◽  
Magnetic Circular Dichroism ◽  
Total Magnetic Moment ◽  
Orbital Moment ◽  
Circular Dichroïsm

Magnetic circular dichroism (MCD) spectra of La 1-x Sr x CoO 3 have been measured at Co 1s and 2p XAS, La 3d and 2p XAS. The contribution of the orbital moment to the total magnetic moment of Co ions became larger with the Sr composition of the La 1-x Sr x CoO 3 system increasing. There was no polarization of the 4f orbital in La but the 5d orbital in La was polarized by the hybridization between the Co 3d orbital and the La 5d orbital.

scholarly journals First principle calculations on structural, electronic, and magnetic properties of CdMAs2 (M = Sc, Ti, V) chalcopyrites

2017 ◽  
Vol 95 (11) ◽  
pp. 1031-1036
Author(s):  
D. Vijayalakshmi ◽  
G. Kalpana
Keyword(s):  
Magnetic Properties ◽  
Spin Polarization ◽  
Magnetic Moment ◽  
Density Functional ◽  
Chalcopyrite Structure ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
Electronic Band ◽  
Effective Spin ◽  
Electronic And Magnetic Properties

Structural, electronic, and magnetic properties of ternary CdMAs2 (M = Sc, Ti, and V) compounds in the chalcopyrite structure have been studied using full-potential linearized augmented plane wave method based on density functional theory. We present a detailed study of electronic band structure, density of states, and magnetic moment of all three compounds within local spin density approximation and generalized gradient approximation. CdMAs2 compounds are derived from chalcopyrite structured CdGeAs2 with the substitution of transition metal (TM) atoms at Ge site. Negative values of formation energy signify that these materials are stable in chalcopyrite structure. Spin-polarized calculations show that the substitution of TM atoms at the group IV site influences the appearance of ferromagnetic state (FM) in CdScAs2 and CdVAs2 compounds. FM in CdScAs2 and CdVAs2 compounds is mainly due to the strong spin polarization of 3d states of M cations and 4p states of As anion. CdVAs2 also exhibits half metallic ferromagnetism with an integer magnetic moment of 1.00μB per formula unit. However, there is no effective spin-polarization of energy states at the Fermi level in CdTiAs2 compound and shows a non-magnetic behaviour.

First-principles Study of Nitrogen Vacancies in GdN

2011 ◽  
Vol 1290 ◽  
Author(s):  
Atchara Punya ◽  
Tawinan Cheiwchanchamnangij ◽  
Alexander Thiess ◽  
Walter R. L. Lambrecht
Keyword(s):  
First Principles ◽  
Exchange Interactions ◽  
Orbital Method ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
Gadolinium Nitride ◽  
Single Positive ◽  
Positive State ◽  
Neutral Charge State ◽  
Nitrogen Vacancies

ABSTRACTThe electronic structure of nitrogen vacancies in gadolinium nitride are studied using the full-potential linearized muffin-tin orbital method in the local spin density approximation with Hubbard U corrections (LSDA+U). The vacancy is found to have two localized defect levels in the gap, one of each spin. The third electron of each vacancy in the neutral state dopes the conduction band. The single positive state is found to be the ground state for Fermi levels located anywhere within the band gap. The vacancy has a net magnetic moment of 1 μB in the neutral charge state. The presence of the vacancy is found to increase the average exchange interactions between Gd atoms and hence the Curie temperature but only by about a factor 2 compared to GdN without vacancies.

Half-Metallic Ferromagnetism in MgS by Doping with Sp-Element: A First-Principles Calculations

2013 ◽  
Vol 665 ◽  
pp. 22-28 ◽  
Author(s):  
Moovendran Yogeswari ◽  
Rajagopalan Umamaheswari ◽  
G. Kalpana
Keyword(s):  
First Principles ◽  
Partial Density ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
First Principles Calculations ◽  
Electronic Band ◽  
Half Metallic ◽  
Exchange Correlation ◽  
Metallic Ferromagnetism ◽  
Half Metallic Ferromagnetism

The first-principles calculations using full potential linearized augmented plane wave method (FP-LAPW) was performed to determine the influence of dopants (N, P, As and Sb) on the electronic structure of MgS in the rock salt structure. In the present work both local spin density approximation (LSDA) and generalized gradient approximation (GGA) were used for exchange correlation potential functional. Among the group V elements N-doping alone induce half-metallic ferromagnetism in MgS host with a magnetic moment of 1.00 μB/f.u. Total energy calculations show that ferromagnetic state is more stable than non-magnetic state in all the compounds. The ground state properties such as equilibrium lattice constant, bulk modulus and bond length were calculated. The spin polarized electronic band structure, total and partial density of states calculations were carried out to study the origin of half-metallic ferromagnetism in these compounds. The difference between two exchange-correlation functions is also analyzed.

scholarly journals STATE OFCoANDMnIN HALF-METALLIC FERROMAGNETCo2MnSiEXPLORED BY MAGNETIC CIRCULAR DICHROISM IN HARD X-RAY PHOTOELECTRON EMISSION AND SOFT X-RAY ABSORPTION SPECTROSCOPIES

SPIN ◽  
2014 ◽  
Vol 04 (04) ◽  
pp. 1440017 ◽  
Author(s):  
GERHARD H. FECHER ◽  
DANIEL EBKE ◽  
SIHAM OUARDI ◽  
STEFANO AGRESTINI ◽  
CHANG-YANG KUO ◽  
...  
Keyword(s):  
Magnetic Moment ◽  
Magnetic Circular Dichroism ◽  
Magnetic Moments ◽  
Magnetic Behavior ◽  
Photoelectron Spectra ◽  
X Rays ◽  
Half Metallic ◽  
X Ray ◽  
Magnetic Dichroism ◽  
X Ray Absorption

The half-metallic Heusler compound Co2MnSi is a very attractive material for spintronic devices because it exhibits very high tunnelling magnetoresistance ratios. This work reports on a spectroscopic investigation of thin Co2MnSi films as they are used as electrodes in magnetic tunnel junctions. The investigated films exhibit a remanent in-plane magnetization with a magnetic moment of about 5 μBwhen saturated, as expected. The low coercive field of only 4 mT indicates soft magnetic behavior. Magnetic dichroism in emission and absorption was measured at the Co and Mn  2p core levels. The photoelectron spectra were excited by circularly polarized hard X-rays with an energy of 6 keV and taken from the remanently magnetized film. The soft X-ray absorption spectra were taken in an induction field of 4 T. Both methods yielded large dichroism effects. An analysis reveals the localized character of the electrons and magnetic moments attributed to the Mn atoms, whereas the electrons related to the Co atoms contribute an itinerant part to the total magnetic moment.

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