Ab initio investigation of the structural and magnetic properties of Ni-Pt-Mn-Ga alloys

2013 ◽  
Vol 1581 ◽  
Author(s):  
Mikhail A. Zagrebin ◽  
Vladimir V. Sokolovskiy ◽  
Vasiliy D. Buchelnikov ◽  
Peter Entel ◽  
Sergey V. Taskaev
Keyword(s):  
Experimental Data ◽  
Magnetic Properties ◽  
Theoretical Calculations ◽  
Magnetic Interactions ◽  
Cubic Phase ◽  
Magnetic Exchange ◽  
Field Methods ◽  
Spin Polarized ◽  
Self Consistent Field ◽  
Structural And Magnetic Properties

ABSTRACTStructural and magnetic properties of Ni2-xPtxMnGa alloys are investigated from first principles calculations with the help of the spin-polarized relativistic Korringa-Kohn-Rostoker and Plane-Wave Self-Consistent Field methods. The atomic chemical disorder at specific site has been implemented using coherent potential approximation. Calculated equilibrium lattice parameters are in a good agreement with experimental data and other theoretical calculations. The composition dependences of the magnetic exchange couplings and the Curie temperature for cubic phase are obtained. Our calculations have shown that an increase content of Pt results to decrease of magnetic interactions between Mn atoms and to change of interaction sign from ferromagnetic type to antiferromagnetic one for composition Ni1.0Pt1.0MnGa. Calculated Curie temperatures are in an agreement with experimental data.

MAGNETIC PROPERTIES OF ICOSAHEDRAL COPPER-COATED COBALT CLUSTERS

2004 ◽  
Vol 11 (01) ◽  
pp. 15-20 ◽  
Author(s):  
BAOLIN WANG ◽  
XIAOSHUANG CHEN ◽  
GUIBIN CHEN ◽  
GUANGHOU WANG ◽  
JIJUN ZHAO
Keyword(s):  
Genetic Algorithm ◽  
Magnetic Properties ◽  
Magnetic Moment ◽  
Tight Binding ◽  
Tight Binding Model ◽  
Significant Modification ◽  
Binding Model ◽  
Model Hamiltonian ◽  
Spin Polarized ◽  
Structural And Magnetic Properties

The structural and magnetic properties of Cu -coated Co clusters are investigated with empirical genetic algorithm simulation and a spin-polarized spd tight-binding model Hamiltonian. In some specific stoichiometric compositions, icosahedral Co n (n=1, 2, 4, 7, 13, 19, 55) clusters perfectly coated with A Cu monolayer or dual layer are obtained. The outer Cu layers lead to significant modification of the magnetic moment of the Co core, depending on the structure and thickness of the Cu layers. The interaction between Cu and Co atoms induces a nonzero magnetic moment for Cu atoms.

Ab-initio modeling of Fe-Mn based alloys and nanoclusters

2011 ◽  
Vol 1296 ◽  
Author(s):  
Peter Entel ◽  
Denis Comtesse ◽  
Heike C. Herper ◽  
Markus E. Gruner ◽  
Mario Siewert ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Ab Initio ◽  
Finite Temperature ◽  
Large Scale ◽  
Exchange Interactions ◽  
The Novel ◽  
Magnetic Exchange ◽  
Simulation Tools ◽  
Transition Metal Alloys ◽  
Structural And Magnetic Properties

ABSTRACTNew methods in steel design and basic understanding of the novel materials require large scale ab initio calculations of ground state and finite temperature properties of transition metal alloys. In this contribution we present ab initio modeling of the structural and magnetic properties of XYZ compounds and alloys where X, Y = Mn, Fe, Co Ni and Z = C, Si with emphasis on the Fe-Mn steels. The optimization of structural and magnetic properties is performed by using different simulation tools. In particular, the finite-temperature magnetic properties are simulated using a Heisenberg model with magnetic exchange interactions from first-principles calculations. Part of the calculations are extended to the nanoparticle range showing how ferromagnetic and antiferromagnetic trends influence the nucleation, morphologies and growth of Fe-Mn-based nanoparticles.

scholarly journals The Impact of Cation Distribution on The Structural and Magnetic Properties of Nonstoichiometric Co0.5Ni0.5+xFe2-xO4 Nanoferrites

2021 ◽  
Author(s):  
Adel Maher Wahba ◽  
Bahaa Eldeen M. Moharam ◽  
Aya Fayez Mahmoud
Keyword(s):  
Magnetic Properties ◽  
Crystallite Size ◽  
Cation Distribution ◽  
Hysteresis Loops ◽  
Lattice Parameter ◽  
Cubic Phase ◽  
Ir Frequencies ◽  
Structural And Magnetic Properties ◽  
Xrd Patterns ◽  
The Impact

Abstract In this work, the impact of nonstoichiometric substitution of Fe3+ cations by Ni2+ ones on the structural and magnetic properties of Co0.5Ni0.5+xFe2-xO4 (0.0 ≤ x ≤ 0.4) nanoferrites synthesized by citric autocombustion method. The cubic phase purity for sintered samples were verified by XRD patterns and FTIR spectra. The crystallite size and microstrain were deduced using Williamson-Hall method. The estimated crystallite size ranges from 55 to 89 nm in agreement with TEM microimages. Hysteresis loops traced using VSM prevailed a regular reduction of saturation magnetization with Ni substitution. Relied on the experimental data of XRD, FTIR, and VSM, cation distribution has been suggested, according to which the nonstoichiometric substitution was compensated by the appearance of higher valance states of Fe, Ni, and Co cations. The suggested cation distribution successfully explained the recorded data of lattice parameter, crystallite size, IR frequencies, magnetization and coercivity.

Extended supramolecular [3×3] Mn9 grid arrays organized by Ag(I) and Au(III)  — structural and magnetic properties

2014 ◽  
Vol 92 (10) ◽  
pp. 966-974 ◽  
Author(s):  
Victoria A. Milway ◽  
Louise N. Dawe ◽  
Laurence K. Thompson
Keyword(s):  
Magnetic Properties ◽  
Metal Ions ◽  
Ground States ◽  
Structural Data ◽  
Outer Sphere ◽  
Molecular Organization ◽  
Gold Complex ◽  
Magnetic Exchange ◽  
Soft Metal ◽  
Structural And Magnetic Properties

A square [3×3] Mn(II)9 supramolecular grid complex with appended ligand SEt groups provides a focus for extended molecular organization through outer-sphere interactions with soft metal ions. Reactions with Ag(I) and Au(III) led to extended 3D arrays in complexes [Mn9(SEt2poap)6]Ag5.75(CF3SO3)2(NO3)9.75(H2O)18 (4), [Mn9(SEt2poap)6][Ag(CN)2]2 [Ag3(CN)5](OH)2(H2O)18 (5), and [Mn9(SEt2poap-3H)4(SEt2poap-2H)2(AuCl3)4] (AuCl4)3.25Cl1.75(H2O)14 (6), involving Mn9 [3×3] square grids with external Ag–S contacts, but with Au(III) extended organization resulting through Au–N ligand contacts only. Structural and magnetic properties are discussed. In the gold complex, magnetic and structural data revealed that Au(III) behaves as an oxidant, leading to oxidation of some corner Mn(II) sites in the grid to Mn(III). Intra-grid magnetic exchange is antiferromagnetic in all cases (J = −4.4 cm−1 (4), J = −5.0 cm−1 (5)), leading to noncompensation of spins because of the odd number of metal ions and low-spin ground states.

Ab initio study of magnetic properties of Fe-Mn-Al Heusler alloys

2013 ◽  
Vol 1581 ◽  
Author(s):  
Vladimir V. Sokolovskiy ◽  
Vasiliy D. Buchelnikov ◽  
Mikhail A. Zagrebin ◽  
Sergey V. Taskaev ◽  
Vladimir V. Khovaylo ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Density Functional ◽  
Heusler Alloys ◽  
Exchange Interactions ◽  
Ferromagnetic Coupling ◽  
Magnetic Exchange ◽  
Functional Theory ◽  
Spin Polarized ◽  
Curie Temperatures

ABSTRACTDensity functional theory (DFT) based on the spin-polarized relativistic Korringa-Kohn-Rostoker (SPR-KKR) method is used to investigate the magnetic properties of nonstoichiometric Fe2+xMn1-xAl Heusler alloys, where 0 ≤ x ≤ 0.9. The composition dependences of the magnetic exchange couplings and the Curie temperature for the cubic L21 phase are obtained. Our simulations have shown that the Fe-Fe nearest neighbors present a strong ferromagnetic coupling. Moreover, these exchange interactions are larger than other interactions. The substitution of Mn by Fe in Fe2+xMn1-xAl (0 ≤ x ≤ 0.9) leads to an increase in the Curie temperature. This tendency and the values of Curie temperatures are in agreement with the experimental results for Fe2+xMn1-xAl (x = 0, and 0.1). The highest Curie temperature was observed for the Fe-richer alloy.

Structural and Magnetic Properties of [BDTA]2[MCl4] [M = Cu (1), Co (2), and Mn (3)], Revealing anS=1/2Square-Lattice Antiferromagnet with Weak Magnetic Exchange

2006 ◽  
Vol 45 (15) ◽  
pp. 5767-5773 ◽  
Author(s):  
Sarah S. Staniland ◽  
Andrew Harrison ◽  
Neil Robertson ◽  
Konstantin V. Kamenev ◽  
Simon Parsons
Keyword(s):  
Magnetic Properties ◽  
Magnetic Exchange ◽  
Structural And Magnetic Properties

scholarly journals Structural and magnetic properties of heusler alloys Pd2MnZ (Z=Ga, Ge, As): AB INITIO study

2018 ◽  
Vol 185 ◽  
pp. 05007 ◽  
Author(s):  
Olga Miroshkina ◽  
Mikhail Zagrebin ◽  
Vladimir Sokolovskiy ◽  
Vasiliy Buchelnikov
Keyword(s):  
Monte Carlo ◽  
Magnetic Properties ◽  
Ab Initio ◽  
Magnetic Moments ◽  
Heusler Alloys ◽  
Magnetic Exchange ◽  
Valence Electrons ◽  
Martensitic State ◽  
Structural And Magnetic Properties ◽  
Exchange Parameters

In this work, we report results of ab initio and Monte Carlo investigations of structural and magnetic properties in a series of Heusler compositions Pd2MnZ (Z = Ga, Ge, As). It was found that for Pd2MnGa and Pd2MnAs, the stable martensitic state is realized on the contrast with Pd2MnGe. The equilibrium lattice parameters for the series of Pd2MnZ (Z = Ga, Ge, As) compounds increase with increasing the number of valence electrons per atom (e/a ratio). Having calculated total magnetic moments and magnetic exchange parameters from ab initio methods, the Curie temperature for Pd2Mn-based alloys has been estimated in the framework of Monte Carlo simulations of Heisenberg model.

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