Magnetic exchange interactions in semiquinone complexes of iron. Structural and magnetic properties of tris(3,5-di-tert-butylsemiquinonato)iron(III) and tetrakis(3,5-di-tert-butylsemiquinonato)tetrakis(3,5-di-tert-butylcatecholato)tetrairon(III)

1989 ◽  
Vol 111 (6) ◽  
pp. 2292-2299 ◽  
Author(s):  
Steven R. Boone ◽  
Gordon H. Purser ◽  
Hsiu Rong Chang ◽  
Michael D. Lowery ◽  
David N. Hendrickson ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Exchange Interactions ◽  
Magnetic Exchange ◽  
Structural And Magnetic Properties

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 Features of the structural and magnetic properties of Pb(TixZr1–xO3)-NiFe1.98Co0.02O4 in the polarized state

Nukleonika ◽  
2017 ◽  
Vol 62 (2) ◽  
pp. 91-94
Author(s):  
Vadim Baev ◽  
Mieczysław Budzyński ◽  
Vladimir Laletin ◽  
Victor Mitsiuk ◽  
Natali Poddubnaya ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Exchange Interactions ◽  
Specific Magnetization ◽  
Polarization Process ◽  
Magnetic Exchange ◽  
Structure Deformation ◽  
Structural And Magnetic Properties ◽  
Crystal Cells

Abstract Composites with a 90%Pb(TixZr1-xO3)-10%NiFe1.98Co0.02O4 composition have been synthesized. It has been established that the polarization of samples resulting from exposure to an electric field for 1 hour of 4 kV/mm in strength at a temperature of 400 K leads to crystal structure deformation. The compression of elementary crystal cells in some areas during polarization of the sample creates conditions suitable for the enhancement of magnetic exchange interactions. It has been found that the polarization process of such compositions leads to increases in specific magnetization and magnetic susceptibility. The analysis of Mössbauer spectra has shown that the polarization of the 90%Pb(TixZr1-xO3)-10%NiFe1.98Co0.02O4 composite leads to significant changes in the effective magnetic fields of iron subspectra in various positions.

scholarly journals Structural and Magnetic Properties of Nanosized Half-Doped Rare-Earth Ho0.5Ca0.5MnO3 Manganite

2022 ◽  
Vol 12 (2) ◽  
pp. 695
Author(s):  
Alessandra Geddo Lehmann ◽  
Giuseppe Muscas ◽  
Maurizio Ferretti ◽  
Emanuela Pusceddu ◽  
Davide Peddis ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Temperature Dependence ◽  
Sol Gel ◽  
Double Exchange ◽  
Exchange Interactions ◽  
Charge Ordering ◽  
Lattice Parameters ◽  
Orthorhombic Symmetry ◽  
Orbital Ordering ◽  
Structural And Magnetic Properties

We investigated the structural and magnetic properties of 20 nm-sized nanoparticles of the half-doped manganite Ho0.5Ca0.5MnO3 prepared by sol-gel approach. Neutron powder diffraction patterns show Pbnm orthorhombic symmetry for 10 K < T < 290 K, with lattice parameters a, b, and c in the relationship c/√2 < a < b, indicating a cooperative Jahn–Teller effect, i.e., orbital ordering OO, from below room temperature. In contrast with the bulk samples, in the interval 250 < T < 300 K, the fingerprint of charge ordering (CO) does not manifest itself in the temperature dependence of lattice parameters. However, there are signs of CO in the temperature dependence of magnetization. Accordingly, below 100 K superlattice magnetic Bragg reflections arise, which are consistent with an antiferromagnetic phase strictly related to the bulk Mn ordering of a charge exchange-type (CE-type), but characterized by an increased fraction of ferromagnetic couplings between manganese species themselves. Our results show that in this narrow band half-doped manganite, size reduction only modifies the balance between the Anderson superexchange and Zener double exchange interactions, without destabilizing an overall very robust antiferromagnetic state.

A Study of Exchange Interactions in R(FeCo)11TiCy (R=Y or Pr) Compounds

2011 ◽  
Vol 170 ◽  
pp. 223-226
Author(s):  
Corneliu Bazil Cizmas ◽  
Lotfi Bessais
Keyword(s):  
Magnetic Properties ◽  
Exchange Interaction ◽  
Magnetic Moment ◽  
Exchange Coupling ◽  
Interaction Strength ◽  
Exchange Interactions ◽  
Field Approximation ◽  
Molecular Field ◽  
Coupling Parameters ◽  
Structural And Magnetic Properties

The exchange interactions in PrFe11-xCoxTiCy (x=0÷2, y≤1), are analyzed on the basis of the structural and magnetic properties of polycrystalline samples. The magnetic properties of polycrystalline isomorphous compounds YFe11-xCoxTiCy have been used in order to determine the T (T=Fe+Co) sub-lattice contributions, such as the T sub-lattice mean magnetic moment and the T-T exchange interaction strength. The exchange coupling parameters JTT, JRT and the recurrent molecular field coefficients nTT, nRT have been calculated in the molecular field approximation (MCA). The effects of Co content and carbonation on the R-T (T=Fe+Co) and on the T-T exchange interactions are analyzed.

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.

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.

Sign in / Sign up

Export Citation Format

Share Document