scholarly journals Effect of Different Mn Doping and Point Vacancy Ratios on the Magnetic Properties of ZnO

2021 ◽  
Author(s):  
Qingyu Hou ◽  
Yuqin Guan ◽  
Zhichao Wang
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moment ◽  
Density Functional ◽  
Oxygen Vacancies ◽  
Doping Amount ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Half Metallic ◽  
Mn Doping ◽  
P Type

The magnetic source of Mn doping and Zn vacancy coexisting in ZnO is controversial. To solve this problem, this work used the generalized gradient approximation first-principle plane-wave ultrasoft pseudopotential + U method based on density functional theory to calculate the effect of different Mn doping to point vacancy ratios on the magnetic properties of ZnO. The formation energy of ZnO with different Mn-substituted Zn (MnZn) to oxygen/zinc vacancy (VO/VZn) ratios can be smaller and more stable in zinc (Zn)-rich conditions than in oxygen (O)-rich conditions. The ZnO system exhibits p-type half-metallic ferromagnetism when the MnZn to VZn ratio is 2: 1 or 2: 2. When the Mn doping amount is constant, the Zn vacancies increase and the total magnetic moment of the doped system decreases. For the ZnO system in which Mn doping and oxygen vacancies coexist, when the amount of oxygen vacancies is constant, with Mn doping increase, the magnetic moment becomes larger. Both Zn22Mn2O22 and Zn20Mn2O24 can achieve ferromagnetic characteristics above room temperature.

DEFECT FORMATION AND MAGNETIC PROPERTIES OF COPPER DOPED ZnO NANOWIRES

2012 ◽  
Vol 26 (13) ◽  
pp. 1250081 ◽  
Author(s):  
LI-BIN SHI
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Oxygen Vacancies ◽  
Defect Formation ◽  
Zno Nanowires ◽  
Energy Calculation ◽  
Generalized Gradient ◽  
Total Energies ◽  
Doped Zno ◽  
P Type

Theoretical calculation based on density functional theory (DFT) and generalized gradient approximation (GGA) has been carried out in studying defect formation energies, ionization energies and magnetic properties of copper doped ZnO nanowires (NW). It is found from formation energy calculation that n-type Cu-doped ZnO NW is non-FM and p-type Cu-doped ZnO NW could be FM. The results show that total energies of FM coupling are lower than those of AFM coupling for majority of 12 configurations, indicating that the FM coupling between Cu atoms is more stable than AFM coupling. The FM stability is interpreted by Cu 3d energy level coupling. In addition, zinc and oxygen vacancies affecting FM coupling is also discussed. It is found that FM coupling can be tuned by zinc and oxygen vacancies.

Density Functional Calculations on Electronic and Magnetic Properties of Fe-Pt Systems

2005 ◽  
Vol 475-479 ◽  
pp. 3103-3106 ◽  
Author(s):  
You Song Gu ◽  
Jian He ◽  
Zhen Ji ◽  
Xiao Yan Zhan ◽  
Yue Zhang ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moment ◽  
Electronic Structures ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Generalized Gradient Approximation ◽  
Experimental Values ◽  
Pseudo Potential

The electronic structures and magnetic properties of Fe-Pt systems were calculated by CASTEP codes, which employed density functional theory, generalized gradient approximation (GGA), Perdew Burke Ernzerh exchange correlation, Pulay density-mixing scheme and Ultra Soft pseudo potential. The band structures and density of states (DOS) were calculated, together with band populations and magnetic properties. The calculated results of α-Fe show the validatiy of this method in predication magnetic properties. It is found that as the Pt concentration increases, Fe 4s and 3d electrons decrease while 4p electrons increase, and the magnetic moment of Fe atom increases. Pt atoms also contribute to the magnetic moment due to polarization. The calculated magnetization agrees with experimental values quite well.

Half-Metallic and Optical Properties of Cu and Cr Codoped AlN

2013 ◽  
Vol 842 ◽  
pp. 205-209
Author(s):  
Yu Qin Fan ◽  
Xue Yao
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Hole Concentration ◽  
First Principles Calculation ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Metallic Material ◽  
Half Metallic ◽  
Type Semiconductor ◽  
P Type

The Half-metallic and optical properties of wurtzite Cu and Cr codoped AlN were investigated by first-principles calculation based on density functional theory (DFT) using the generalized gradient approximation (GGA) for the exchange-correlation potential. It is shown that the Cu and Cr codoped AlN is a typical half-metallic material at the equilibrium lattice constant. As a p-type semiconductor, there exhibits higher hole concentration in Cu and Cr codoped AlN comparing with Cu doped AlN or Cr doped AlN, which indicates a significant increase in TC. This result suggests that it is possible to achieve high TC materials by Cu and Cr codoped AlN. In addition, the band gap of Cu and Cr codoped AlN is reduced and the absorption ability to ultraviolet light is expanded obviously, a noticeable red-shift of the absorption spectra edge is observed in the Cu and Cr codoped system and two new absorption peaks appear at around 28 nm and 225 nm.

scholarly journals Structural, elastic, electronic, and magnetic properties of quaternary alloys BBi0.75Mn0.125N0.125 : a first-principles study

2020 ◽  
Vol 66 (5 Sept-Oct) ◽  
pp. 627
Author(s):  
S. Tab ◽  
A. Boudali ◽  
M. Berber ◽  
M. Driss khodja ◽  
O. Lhaj El Hachemi ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Ferromagnetic Phase ◽  
Generalized Gradient ◽  
Quaternary Alloys ◽  
Functional Theory ◽  
Half Metallic ◽  
Electronic And Magnetic Properties ◽  
First Time ◽  
Metallic Ferromagnetism

In this study, we have employed the first-principle methods based on density functional theory to investigate the structural, elastic, electronic and magnetic properties of BBi0.75Mn0.125N0.125. The exchange and correlation potential are described by the generalized gradient approximation of Perdew, Burke and Ernzerhof (GGA-PBEsol) + SOC coupled with TB-mBJ approaches. The studied structure show that the compound BBi0.75Mn0.125N0.125 is stable in ferromagnetic phase, the elastic property indicate that the structure is brittle and mechanically stable. The half metallic description is predicted with energy spin band gap in spin up channel. The structure attributed half-metallic ferromagnetism could be suitable for spintronics devices. To our knowledge, this is the first time that a study has been done on this alloy and we would like it to serve as a reference for the next studies.

THE FIRST PRINCIPLES CALCULATION OF STRUCTURAL, ELECTRONIC AND MAGNETIC PROPERTIES OF MnXY (X = Ru, Rh AND Y = Ga, Ge, Sb) ALLOYS

2011 ◽  
Vol 25 (26) ◽  
pp. 2079-2090 ◽  
Author(s):  
S. M. MONIRI ◽  
Z. NOURBAKHSH ◽  
M. MOSTAJABODAAVATI
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moment ◽  
Density Functional ◽  
Magnetic Moments ◽  
Heusler Alloys ◽  
Local Magnetic Moment ◽  
First Principles Calculation ◽  
Functional Theory ◽  
Half Metallic ◽  
Electronic And Magnetic Properties

The structural, electronic and magnetic properties of MnXY ( X = Ru , Rh and Y = Ga , Ge , Sb ) Heusler alloys are studied using density functional theory by the WIEN2k package. These materials are ferromagnetic. Also they have some interesting half-metallic properties. The electron density of states, total and local magnetic moment of these alloys are calculated. We have calculated the effective Coulomb interaction U eff using the ab initio method. We have compared the magnetic moments of these alloys in GGA and LDA + U with the Slater–Pauling rule. Furthermore the effect of hydrostatic pressure on the magnetic moment of these alloys is studied. The calculated results are fitted with a second order polynomial.

ELECTRON DOPING EFFECTS ON ELECTRONIC AND MAGNETIC PROPERTIES IN Sr2FeReO6

2011 ◽  
Vol 25 (29) ◽  
pp. 2259-2267 ◽  
Author(s):  
Q. F. LI ◽  
L. WANG ◽  
J. L. SU
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Ferromagnetic Interaction ◽  
Half Metallic ◽  
Electronic And Magnetic Properties ◽  
Doping Effects ◽  
Electronic Doping ◽  
La Doped

We have investigated the electronic and magnetic properties of electron-doped Sr 2-x La x FeReO 6 (x = 0.0, 0.25, 0.5) using first-principles density functional theory within the generalized gradient approximation (GGA) and GGA + U schemes. Our results reveal that the symmetry of the La -doped compounds is decreased from tetragonal I4/m for perfect sample to monoclinic P21/n. With increasing La content the absolute magnetic moment of the Re site increases distinctly and the doped electrons are considered to occupy mainly the down-spin Re 5d band from the band calculation. Electronic doping is found to enhance the Curie temperature (T c ) and stabilize the ferromagnetic half-metallic ground states of Sr 2 FeReO 6. And it is found that the increase of T c is mainly caused by the increase of ferromagnetic interaction between the Fe – O – Fe .

An Investigation of Half-Metallic Ferromagnets Behavior in Hg2CuTi-Type Heusler Alloy Ti2FeAl by Using GGA

2012 ◽  
Vol 535-537 ◽  
pp. 1291-1294 ◽  
Author(s):  
Xiu De Yang ◽  
Bo Wu ◽  
Song Zhang
Keyword(s):  
Density Functional Theory ◽  
Heusler Alloy ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Half Metallic ◽  
Generalized Gradient Approximation ◽  
Indirect Exchange ◽  
The Density Functional Theory ◽  
Direct Hybridization

By using generalized gradient approximation (GGA) scheme within the density functional theory (DFT), the electronic and magnetic properties of Hg2CuTi-type Heusler alloy Ti2FeAl were investigated. The results reveal that a 100% spin polarization appears at Fermi level (εF) in Ti2FeAl, and is maintained during lattice range of 5.1Å~6.2Å. Ti2FeAl is one of stable Half-Metallic Ferromagnets (HMF) with a spin-minority gap of 0.5 eV at εF and total magnetic moment of 1μB per unit cell. 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.

scholarly journals Stability and magnetic properties of isomorphous substituted Si7-xMnx+

2018 ◽  
Vol 56 (1) ◽  
pp. 64
Author(s):  
Nguyen Thanh Tung ◽  
Nguyen Thi Mai ◽  
Ngo Tuan Cuong
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Magnetic Moment ◽  
Density Functional ◽  
Basis Set ◽  
Pentagonal Bipyramid ◽  
Functional Theory ◽  
Electronic Configurations ◽  
Method Of Density Functional ◽  
Optimized Geometries

The optimized geometries, stability, and magnetic properties of cationic clusters Si7+, Si6Mn+, and Si5Mn2+ have been determined by the method of density functional theory using the B3P86/6-311+G(d) functional/basis set. Their electronic configurations have been analyzed to understand the influence of substituting Si atoms by Mn atoms on the structural and magnetic aspects of Si7+. It is shown that the manganese dopant does not alter the structure of the silicon host but significantly changes its stability and magnetism. In particular, while the magnetic moment of Si7+ is 1 mB, Si5Mn2+ exhibits a strong magnetic moment of 9 mB and that of Si6Mn+ takes a relatively high value of 4 mB. Among studied clusters, the pentagonal bipyramid Si5Mn2+ is assigned as the most stable one.

Electronic Structure and Ferromagnetic Properties of Doped Calcium Sulfide Ca1−xTMxS (TM = V, Cr and Co)

SPIN ◽  
2020 ◽  
Vol 10 (02) ◽  
pp. 2050013 ◽  
Author(s):  
Amina Aiche ◽  
Abdelkader Tadjer ◽  
Hadj Moulay Ahmed Mazouz ◽  
Bendouma Doumi ◽  
Houari Khachai
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
Density Functional ◽  
Double Exchange ◽  
Ferromagnetic State ◽  
Spin Splitting ◽  
Full Potential ◽  
Generalized Gradient ◽  
Metallic Behavior ◽  
Half Metallic

The electronic structure and magnetic properties of diluted Ca[Formula: see text]TMxS (TM[Formula: see text][Formula: see text][Formula: see text]V, Cr and Co) in the rocksalt structure at concentrations [Formula: see text], 0.125 and 0.25 were studied using the full-potential linearized augmented plane wave approximation of the density functional theory with the Wu-Cohen generalized gradient approximation (WC-GGA) and the Tran–Blaha-modified Becke–Johnson (TB-mBJ) potential. Features such as lattice constant, bulk modulus, spin-polarized band structures, total and local densities of states and magnetic properties have been computed. The electronic structure show that Ca[Formula: see text](V, Cr)xS at all the studied concentrations and the diluted Ca[Formula: see text]CoxS with [Formula: see text] compounds are half-metallic ferromagnets with spin polarization of 100%. The calculated total magnetic moments for Ca[Formula: see text]VxS and Ca[Formula: see text]CoxS show the same integer value of 3[Formula: see text][Formula: see text] per formula unit and Ca[Formula: see text]CrxS exhibit a total magnetic moment of 4[Formula: see text][Formula: see text], which confirm the half-metallic behavior of these compounds. We also calculated the values of the band edge spin splitting of the valence and conduction bands and the exchange constants. We have found that the ferromagnetic state is stable by the p-d exchange associated with the double-exchange mechanism. The diluted Ca[Formula: see text](V,Cr,Co)xS are found to be new promising candidates for spintronic applications.

scholarly journals Structural, Electronic, and Magnetic Properties of Mn4N Perovskite: Density Functional Theory Calculations and Monte Carlo Study

2019 ◽  
Vol 33 (5) ◽  
pp. 1507-1512 ◽  
Author(s):  
A. Azouaoui ◽  
M. El Haoua ◽  
S. Salmi ◽  
A. El Grini ◽  
N. Benzakour ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Monte Carlo ◽  
Magnetic Properties ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Generalized Gradient ◽  
Critical Temperatures ◽  
Metallic Behavior ◽  
Functional Theory ◽  
Electronic And Magnetic Properties

AbstractIn this paper, we have studied the structural, electronic, and magnetic properties of the cubic perovskite system Mn4N using the first principles calculations based on density functional theory (DFT) with the generalized gradient approximation (GGA). The obtained data from DFT calculations are used as input data in Monte Carlo simulation with a mixed spin-5/2 and 1 Ising model to calculate the magnetic properties of this compound, such as the total, partial thermal magnetization, and the critical temperatures (TC). The obtained results show that Mn4N has a ferrimagnetic structure with two different sites of Mn in the lattice and presents a metallic behavior. The obtained TC is in good agreement with experimental results.

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