scholarly journals Robust manipulation of magnetism in LaAO3/BaTiO3 (A = Fe, Mn and Cr) superstructures by ferroelectric polarization

IUCrJ ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 189-196 ◽  
Author(s):  
Dong Chen ◽  
Guangbiao Zhang ◽  
Zhenxiang Cheng ◽  
Shuai Dong ◽  
Yuanxu Wang
Keyword(s):  
Magnetic Ordering ◽  
Exchange Interactions ◽  
Perovskite Oxide ◽  
Oxygen Octahedra ◽  
Ferroelectric Polarization ◽  
Structural Basis ◽  
Generalized Gradient ◽  
Metallic Behavior ◽  
Spin Orbital ◽  
Ferromagnetic Ordering

Robust control of magnetism is both fundamentally and practically meaningful and highly desirable, although it remains a big challenge. In this work, perovskite oxide superstructures LaFeO3/BaTiO3 (LFO/BTO), LaMnO3/BaTiO3 (LMO/BTO) and LaCrO3/BaTiO3 (LCO/BTO) (001) are designed to facilitate tuning of magnetism by the electric field from ferroelectric polarization, and are systemically investigated via first-principles calculations. The results show that the magnetic ordering, conductivity and exchange interactions can be controlled simultaneously or individually by the reorientation of the ferroelectric polarization of BTO in these designed superstructures. Self-consistent calculations within the generalized gradient approximation plus on-site Coulomb correction did not produce distinct rotations of oxygen octahedra, but there were obvious changes in bond length between oxygen and the cations. These changes cause tilting of the oxygen octahedra and lead to spin, orbital and bond reconstruction at the interface, which is the structural basis responsible for the manipulation. With the G-type antiferromagnetic (G-AFM) ordering unchanged for both ±P cases, a metal–insulator transition can be observed in the LFO/BTO superstructure, which is controlled by the LFO thin film. The LMO/BTO system has A-type antiferromagnetic (A-AFM) ordering with metallic behavior in the +P case, while it shifts to a half-metallic ferromagnetic ordering when the direction of the polarization is switched. LCO/BTO exhibits C-type antiferromagnetic (C-AFM) and G-AFM orders in the +P and −P cases, respectively. The three purpose-designed superstructures with robust intrinsic magnetoelectric coupling are a particularly interesting model system that can provide guidance for the development of this field for future applications.

Magnetic properties of cobalt single layer added on graphene: A density functional theory study

2015 ◽  
Vol 29 (02) ◽  
pp. 1450262 ◽  
Author(s):  
M. Afshar ◽  
H. Doosti
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Single Layer ◽  
Magnetic Ordering ◽  
Polarization Degree ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Half Metallic ◽  
Cobalt Layer ◽  
Ferromagnetic Ordering

In this paper, we have demonstrated magnetic ordering of single cobalt layer added on graphene using relativistic density functional theory at the level of generalized gradient approximation. We have shown that the single Co layer added on graphene show ferromagnetic ordering with perpendicular alignment to the graphene sheet. In the presence of spin-orbit coupling, a spin-polarization degree of about 92% was found for this quasi-two-dimensional magnetic system where it is shown a nearly half-metallic feature.

scholarly journals Structural Stability and Magnetic Ordering in BiFeO3 Perovskite Oxide: A Comparative Study GGA+U vs L(S)DA+U

2020 ◽  
Vol 62 (1) ◽  
pp. 52-70
Author(s):  
M. Derras ◽  
N. Hamdad
Keyword(s):  
Data Storage ◽  
Density Functional ◽  
Magnetic Ordering ◽  
Perovskite Oxide ◽  
Cubic Phase ◽  
Full Potential ◽  
Spin Effect ◽  
Local Spin Density Approximation ◽  
Generalized Gradient ◽  
Antiferromagnetic Ordering

AbstractAb initio calculations of BiFeO3 magnetic perovskite are carried. Accurate density functional theory calculations were performed considering a U-Hubbard correction (DFT+U) to account for on-site Coulomb interactions of the 3d-Fe states. We have applied the Full-potential linearized augmented plane waves (FP-LAPW) method. Exchange-correlation effects are treated using the Local Spin Density approximation (L(S)DA+U) vs generalized gradient approximations (GGA+U). Equilibrium lattices agree very well with other theoretical and experimental data. The magnetization energy differences between Spin Up and Spin Dn states are small. Spin effect and magnetic moment obtained from subsequent (L(S)DA+U) and (GGA+U) calculations are also discussed in different magnetic configurations: The Ferromagnetic cubic phase (Pm-3m), The A-type Antiferromagnetic (P4/mmc) and The G-type Antiferromagnetic (Fm-3m). The nature of magnetism arises mainly from the Fe-site exhibiting a G-type antiferromagnetic ordering. The electronic structure shows that BiFeO3 has a metallic band gap. This multiferroic exhibit strong hybridization of the 3d-Fe and 2p-O orbitals. Therefore, the Multiferroic BiFeO3 perovskite has driven significant research interest due to their promising technological potential. It’s a good candidate for potential applications in spintronic, and to aid the development of the next generation of data storage and multi-functional technological devices.

scholarly journals First principles study of electronic, elastic, optical and magnetic properties of Rh2MnX (X=Ti, Hf, Sc, Zr, Zn) Heusler alloys

2020 ◽  
Author(s):  
Emre GÜLER ◽  
Melek GÜLER ◽  
Şule Uğur ◽  
Gökay Uğur
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Correlation Energy ◽  
Heusler Alloys ◽  
Optical Data ◽  
Generalized Gradient ◽  
Metallic Behavior ◽  
Functional Theory ◽  
Optical And Magnetic Properties ◽  
Ferromagnetic Ordering

We report the electronic, elastic, mechanical, optical and magnetic properties of Rh2MnX (X=Ti, Hf, Sc, Zr, Zn) Heusler alloys performed within density functional theory (DFT). The generalized gradient approximation (GGA) was used for calculations in the context of the Perdew-Burke-Ernzerhof (PBE) exchange-correlation energy treatment. The computed elastic constants and elastic moduli show that all investigated alloys are mechanically stable and ductile. It has been found that the magnitudes of the theoretical Vickers hardness values of these alloys are in the range of Ti> Sc> Zr> Hf> Zn. Also, a typical metallic behavior is obtained for all alloys after agreement of mechanical, electronic and optical data. On the other side, all alloys show strong ferromagnetic ordering following the magnetic moment (B) rank of Ti > Zr > Hf > Sc > Zn. Our calculated B data also agree well with the former theoretical results of Rh2MnX (X=Ti, Hf, Sc, Zr, Zn) Heusler alloys.

Exchange interactions and the nature of magnetic ordering in Zn0.6Mn2.4O4 particles

2020 ◽  
Vol 599 ◽  
pp. 412460
Author(s):  
N. Rajeesh Kumar ◽  
R. Kalai Selvan ◽  
Leonid Vasylechko ◽  
P. Saravanan ◽  
Mohindar S. Seehra
Keyword(s):  
Magnetic Ordering ◽  
Exchange Interactions

scholarly journals First-principle investigations of structural and electronic properties of TMAl (TM = Fe, Co, and Ni) transition metal aluminides

2015 ◽  
Vol 33 (2) ◽  
pp. 251-258
Author(s):  
Bendouma Doumi ◽  
Allel Mokaddem ◽  
Mustapha Ishak-Boushaki ◽  
Miloud Boutaleb ◽  
Abdelkader Tadjer
Keyword(s):  
Transition Metal ◽  
Electronic Properties ◽  
Density Functional ◽  
First Principle ◽  
Generalized Gradient ◽  
Metallic Behavior ◽  
Plane Wave Method ◽  
Structural And Electronic Properties ◽  
The Difference ◽  
Metal Aluminides

AbstractIn the present work, we have investigated the structural and electronic properties of TMAl (TM = Fe, Co, and Ni) transition metal aluminides in the B2 structure, using first-principle calculations of the density functional theory (DFT) based on the linearized augmented plane wave method (FP-LAPW) as implemented in the WIEN2k code, in which the energy of exchange and correlation are treated by the generalized gradient approximation (GGA), proposed in 1996 by Perdew, Burke and Ernzerhof (PBE). The ground state properties have been calculated and compared with other calculations, and the electronic structures of all FeAl, CoAl, and NiAl compounds exhibited a metallic behavior. It was depicted that the density of states is characterized by the large hybridization between the s-p (Al) and 3d (Fe, Co, and Ni) states, which creates the pseudogap in the region of anti-bonding states. Moreover, the band structures of FeAl, CoAl, and NiAl are similar to each other and the difference between them is in the energy level of each band relative to the Fermi level.

DFT study of structural, elastic, electronic, magnetic, thermal and transport properties of new multifunctional NiVSn half-Heusler for spintronic and thermoelectric applications

2021 ◽  
pp. 2150202
Author(s):  
Y. Bouldiab ◽  
S. terkhi ◽  
Z. Aziz ◽  
F. Bendahma ◽  
M. A. Bennani ◽  
...  
Keyword(s):  
Transport Properties ◽  
Thermoelectric Properties ◽  
Density Functional ◽  
Extreme Temperature ◽  
Ferromagnetic State ◽  
Debye Model ◽  
Generalized Gradient ◽  
Metallic Behavior ◽  
Half Metallic ◽  
High Seebeck Coefficient

In this work, the first-principles density functional calculations of the structural, elastic, electronic, magnetic, thermal and thermoelectric properties of NiVSn half-Heusler compound are carried out. The exchange and correlation potential are treated by using Generalized Gradient approximation of Perdew, Burke and Ernzerhof (GGA-PBE), GGA plus Tran–Blaha-modified Becke–Johnson (mBJ-GGA) approach and mBJ-GGA+U where U is the Hubbard on-site Coulomb interaction correction (mBJ-GGA+U). Structural calculations revealed that NiVSn is stable in type 1 structure ferromagnetic state. Elastic properties show that our compound is mechanically stable, ductile and anisotropic. The results of the band structures and density of states display a half metallic behavior of NiVSn with an indirect bandgap of 0.476, 0.508 and 0.845 eV by using GGA-PBE, mBJ-GGA, and mBJ-GGA+U, respectively. The total magnetic moment calculated is integer of 1 [Formula: see text]B confirming a half metallic behavior of NiVSn and follows the well-known Slater–Pauling rule ([Formula: see text]); therefore, the studied compound is suitable for application in spintronic fields. The thermodynamic properties such as bulk modulus, the heat capacity, the Debye temperature, and the thermal expansion coefficient are investigated using quasi-harmonic Debye model (QHDM). The thermal results show that NiVSn can be applied in extreme temperature and pressure conditions. The thermoelectric properties are studied employing the BoltzTrap code. The calculated transport properties are very interesting for the spin-down channel with high electrical conductivity, high Seebeck coefficient, and figure of merit value approaching unity. As a result, the half-Heusler alloy NiVSn is a promoter for conventional thermoelectric materials.

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.

Magnetic ordering and exchange interactions in multiferroicGaFeO3

2007 ◽  
Vol 75 (6) ◽  
Author(s):  
Myung Joon Han ◽  
Taisuke Ozaki ◽  
Jaejun Yu
Keyword(s):  
Magnetic Ordering ◽  
Exchange Interactions

A MONTE CARLO SIMULATION OF MAGNETIC ORDERING IN ISING CUBIC FERROSPINELS

2004 ◽  
Vol 03 (02) ◽  
pp. 179-188 ◽  
Author(s):  
N. STANICA ◽  
F. CIMPOESU ◽  
GIANINA DOBRESCU ◽  
V. CHIHAIA ◽  
LUMINITA PATRON ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Magnetic Properties ◽  
Simple Model ◽  
Magnetic Ordering ◽  
Exchange Interactions ◽  
Monte Carlo Studies ◽  
Quantum Spins ◽  
Type Lattice ◽  
Insight Into

This work signifies the next step in our way in the magnetic properties simulation of spin clusters and extended networks containing quantum spins, by original FORTRAN codes based on Heisenberg–Dirac–VanVleck (HDVV) or Ising approaches, using Full Diagonalization Heisenberg Matrix (FDHM) or Monte Carlo–Metropolis (MCM) procedure, respectively. We present the results of magnetic Monte Carlo studies on a magnetite type lattice, Ising model ferrimagnet that provide insight into the exchange interactions involved in Cubic Ferrospinels. We have demonstrated that a comparatively simple model can reproduce ferrimagnetic behavior of ferrospinels, particularly for magnetite.

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