scholarly journals Electronic and Magnetic Properties Studies on Mn and Oxygen Vacancies Codoped Anatase TiO2

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Zhongpo Zhou ◽  
Xinwei Yang ◽  
Haiying Wang ◽  
Zhaorui Zou ◽  
Jingjing Guo
Keyword(s):  
Magnetic Properties ◽  
Oxygen Vacancy ◽  
Magnetic Moment ◽  
Oxygen Vacancies ◽  
Nearest Neighbor ◽  
Anatase Tio2 ◽  
Experimental Results ◽  
Mn Doping ◽  
Electronic And Magnetic Properties ◽  
Calculation Results

The electronic and magnetic properties of Mn and oxygen vacancies codoped anatase TiO2were investigated. The calculated results showed that the TiO2codoped with Mn and oxygen vacancies have a magnetic moment value of 3.415 μBper Ti31MnO63supercell. Furthermore, Ti31MnO63gets the lowest energy with a geometrical optimization where the Mn ions locate at the nearest-neighbor sites of the oxygen vacancy. And experimental results indicated the magnetism is associated with the defects of Mn ions and oxygen vacancies induced by the Mn doping, which is consistent with the calculation results.

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.

Influence of Oxygen Vacancy on Electronic and Magnetic Properties in Cr Doped SnO2 Superlattice

2011 ◽  
Vol 80 (12) ◽  
pp. 124709 ◽  
Author(s):  
Lei Jiang ◽  
Yao Lu ◽  
Chang-Wen Zhang ◽  
Pei-Ji Wang ◽  
Xian-Yang Feng ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Oxygen Vacancy ◽  
Electronic And Magnetic Properties

Oxygen vacancy migration in CSZ using density functional theory

2008 ◽  
Vol 1122 ◽  
Author(s):  
Byeong-Eon Lee ◽  
Dae-Hee Kim ◽  
Yeong-Cheol Kim
Keyword(s):  
Density Functional Theory ◽  
Oxygen Vacancy ◽  
Density Functional ◽  
Oxygen Vacancies ◽  
Nearest Neighbor ◽  
Functional Theory ◽  
The Third ◽  
Vacancy Migration ◽  
Neighbor Site ◽  
Formation Energies

AbstractWe studied oxygen migration in calcia-stabilized cubic zirconia (CSZ) using density functional theory. A Ca atom was substituted for a Zr atom in a 2×2×2 ZrO2 cubic supercell, and an oxygen vacancy was produced to satisfy the charge neutrality condition. We found that the formation energies of an oxygen vacancy, as a function of its location with respect to the Ca atom, were varied. The relative formation energies of the oxygen vacancies located at the first-, second-, third-, and fourth-nearest-neighbors were 0.0, −0.07, 0.19, and 0.19 eV, respectively. Therefore, the oxygen vacancy located at the second-nearest-neighbor site of the Ca atom was the most favorable, the oxygen vacancy located at the first-nearest-neighbor site was the second most favorable, and the oxygen vacancies at the third- and fourth-nearest-neighbor sites were the least favorable. We also calculated the energy barriers for the oxygen vacancy migration between oxygen sites. The energy barriers between the first and the second nearest sites, the second and third nearest sites, and the third and fourth nearest sites were 0.11, 0.46, and 0.23 eV, respectively. Therefore, the oxygen vacancies favored the first- and second-nearest-neighbor oxygen sites when they drifted under an electric field.

Oxygen vacancy-confined CoMoO4@CoNiO2 nanorod arrays for oxygen evolution with improved performance

2019 ◽  
Vol 48 (27) ◽  
pp. 10116-10121 ◽  
Author(s):  
Xiaoqiang Du ◽  
Guangyu Ma ◽  
Xiaoshuang Zhang
Keyword(s):  
Oxygen Vacancy ◽  
Oxygen Evolution ◽  
Adsorption Energy ◽  
Active Sites ◽  
Oxygen Vacancies ◽  
Dft Calculation ◽  
Catalytic Properties ◽  
Nanorod Arrays ◽  
Calculation Results ◽  
Improved Performance

Experimental and DFT calculation results show that the presence of oxygen vacancies can decrease the adsorption energy of intermediates at active sites and facilitate the adsorption of intermediates, thus improving the catalytic properties.

Tunable electronic structure and magnetic moment in C2N nanoribbons with different edge functionalization atoms

2017 ◽  
Vol 19 (23) ◽  
pp. 15021-15029 ◽  
Author(s):  
Yusheng Wang ◽  
Nahong Song ◽  
Min Jia ◽  
Dapeng Yang ◽  
Chikowore Panashe ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Electronic Structure ◽  
Magnetic Moment ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Electronic And Magnetic Properties

First principles calculations based on density functional theory were carried out to study the electronic and magnetic properties of C2N nanoribbons (C2NNRs).

Theoretical Studies of the Structural, Electronic and Magnetic Properties of the CoFeCeZ (Z = P, As and Sb) Quaternary Heusler Alloys

SPIN ◽  
2019 ◽  
Vol 10 (01) ◽  
pp. 2050002 ◽  
Author(s):  
F. N. Gharbi ◽  
I. E. Rabah ◽  
M. Rabah ◽  
H. Rached ◽  
D. Rached ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moment ◽  
Heusler Alloys ◽  
Ferromagnetic Phase ◽  
Full Potential ◽  
Half Metallicity ◽  
Electronic And Magnetic Properties ◽  
Quaternary Heusler Alloys ◽  
Lmto Method ◽  
High Magnetic Moment

In this paper, we investigate the structural, electronic and magnetic properties of CoFeCrZ ([Formula: see text], As,Sb) quaternary Heusler alloy, using the first-principles full potential linear muffin-tin orbital (FP-LMTO) method within the spin gradient generalized approximation (GGA) for the exchange and correlation potential. Our results demonstrate that in ferromagnetic phase, the all alloys CoFeCrZ are stable in type-1 configuration and are half-metallic ferromagnets (HMF) with gaps of 0.99[Formula: see text]eV, 0.57[Formula: see text]eV and 0.70[Formula: see text]Ev, respectively. The obtained negative formation energy shows that CoFeCrZ alloys have strong structural stability. The calculated total magnetic moment, [Formula: see text] for all alloys exhibit Slater-Pauling rule, [Formula: see text]. At zero pressure, the three alloys shown 100% spin-polarization at Fermi–level [Formula: see text] with high Curie temperatures [Formula: see text]. Our calculation indicate also that the half-metallicity and high magnetic moment of CoFeCrP, CoFeCrAs and CoFeCrSb are robust against the lattice compression (up to 7.80%, 5.40% and 11%, respectively). On the basis of these results, it is suggested that the CoFeCrZ Heusler could be suitable for spintronics devices applications.

Electronic and Magnetic Properties of Half Metallic Heusler Alloy Co2mnsi: A First-Principles Study

2017 ◽  
pp. 31-36
Author(s):  
Prakash Sharma ◽  
Gopi Chandra Kaphle
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moment ◽  
Heusler Alloy ◽  
Density Functional ◽  
Heusler Alloys ◽  
Tight Binding ◽  
Lattice Parameter ◽  
Half Metallic ◽  
Electronic And Magnetic Properties ◽  
Sphere Approximation

Heusler alloys have been of great interest because of their application in the field of modern technological word. Electronic and magnetic properties of Co, Mn, Si and the Heusler alloy Co2MnSi have been studied using Density functional theory based Tight Binding Linear Muffin Tin Orbital with Atomic Sphere Approximation (TB-LMTO-ASA) approach. From the calculation lattice parameter of optimized structure of Co, Mn, Si and Co2MnSi are found to be 2.52A0 , 3.49A0 , 5.50A0 , 5.53A0 respectively. Band structure calculations show that Co and Mn are metallic, Si as semi-conducting while the Heusler alloy Co2MnSi as half-metallic in nature with band gap 0.29eV. The charge density plot indicates major bonds in Co2MnSi are ionic in nature. Magnetic property has been studied using the density of states (DOS), indicating that Co and Co2MnSi are magnetic with magnetic moment 2.85μB and 4.91μB respectively. The contribution of orbitals in band, DOS and magnetic moment are due to d-orbitals of Co and Mn and little from s and p-orbital of Si in Co2MnSi.The Himalayan Physics Vol. 6 & 7, April 2017 (31-36)

Defect-Mediated Mechanics in Non-Stoichiometric Oxide Films

MRS Advances ◽  
2018 ◽  
Vol 3 (10) ◽  
pp. 537-545 ◽  
Author(s):  
Jessica G. Swallow ◽  
Mostafa Youssef ◽  
Krystyn J. Van Vliet
Keyword(s):  
Thin Films ◽  
Elastic Modulus ◽  
Oxygen Vacancy ◽  
Elastic Properties ◽  
Oxygen Vacancies ◽  
Experimental Results ◽  
Chemical Expansion ◽  
Chemomechanical Coupling ◽  
Defect Content ◽  
Material Volume

ABSTRACTChemomechanical coupling is a hallmark of the functional oxides that are used widely for energy conversion and storage applications including solid oxide fuel cells (SOFCs). These oxides rely on the presence of oxygen vacancies to enable important properties including ionic conductivity and gas exchange reactivity. However, such defects can also facilitate chemical expansion, or coupling between material volume and defect content. Such chemomechanical coupling is particularly relevant with the recent interest in thin film SOFCs which have the potential to decrease operating temperatures and enable portable applications. Thin films present a particular challenge for modelling, as experimental results indicate that film defect chemistry can differ significantly from bulk counterparts under the same experimental conditions. In this study, we explore the influence of point defects, including oxygen vacancies and cation dopants, on the elastic properties of a model material, PrxCe1-xO2-δ (PCO), using density functional theory (DFT + U) simulations. Previously, we showed that PCO films exhibit a decrease in Young’s elastic modulus E due to chemical expansion, but that this decrease can be larger than predicted based on bulk defect models. Here, we apply DFT + U to show that the biaxial elastic modulus of PCO decreases with increased oxygen vacancy content in both bulk and membrane forms. We consider the relative influences of oxygen vacancies and cation dopants on this trend, and highlight local structural changes in the presence of such defects. By relating our computational and experimental results, we evaluate the relative importance of increased oxygen vacancy content and finite thickness on the mechanical properties of oxides that are subject to chemical expansion under operando conditions. This work informs the design of μ-SOFCs, emphasizing the need to characterize thin films separately from bulk counterparts and demonstrating how functional defect content can influence development of stress and strain in devices by changing both material volume and elastic properties.

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