Electronic Structure of Tunable Materials MnAl and MnGa

1999 ◽  
Vol 603 ◽  
Author(s):  
A. N. Chantis ◽  
D. O. Demchenko ◽  
A. G. Petukhov ◽  
W. R. L. Lambrecht
Keyword(s):  
Magnetocrystalline Anisotropy ◽  
Magnetic Moments ◽  
Anisotropy Energy ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
Lattice Constants ◽  
Lmto Method ◽  
Sphere Approximation ◽  
Good Agreement ◽  
Magnetocrystalline Anisotropy Energy

AbstractWe present first-principle calculations of equilibrium lattice constants, band structures, densities of states and magnetocrystaline anisotropy energy for bulk MnAl and MnGa. The linear-muffin-tin-orbital (LMTO) method has been used within the framework of the local spin density approximation (LSDA). Both the atomic sphere approximation (ASA) and the full-potential (FP) versions of the LMTO method were employed. Calculations of the equilibrium structures were performed both for paramagnetic and ferromagnetic phases of MnAl and MnGa. The results of these calculations indicate that the large tetragonal distortion of the crystal structure is caused by the spin polarization of the electronic subsystem. The magnetocrystalline anisotropy energy per unit cell for MnAl and MnGa is shown to be 0.244 meV and 0.422 meV respectively. This is in good agreement with previous calculations and some experimental data. Magnetic moments, density of states and dependence of magnetocrystalline anisotropy energy on the lattice constant ration c/a are also found to be in good agreement with previous results.

FIRST-PRINCIPLES CALCULATION OF THE MAGNETOCRYSTALLINE ANISOTROPY ENERGY FOR THE PSEUDOBINARY COMPOUND Y(Co1−xFex)5

1993 ◽  
Vol 07 (01n03) ◽  
pp. 745-748 ◽  
Author(s):  
JOAKIM TRYGG ◽  
LARS NORDSTRÖM ◽  
BÖRJE JOHANSSON
Keyword(s):  
Magnetocrystalline Anisotropy ◽  
Energy Difference ◽  
Anomalous Behavior ◽  
Anisotropy Energy ◽  
First Principles Calculation ◽  
Atomic Sphere ◽  
Lmto Method ◽  
Sphere Approximation ◽  
Total Energy Difference ◽  
Magnetocrystalline Anisotropy Energy

From the experimental behavior of the magnetocrystalline anisotropy energies of the pseudobinary compounds Y(Co1−xFex)5, it has been argued that the magnetocrystalline anisotropy energies for YCo5 and the hypothetical compound YFe5 will have different signs. This anomalous behavior is attributed to the change of the number of 3d electrons and their orbital moments when proceeding from YFe5 to YCo5. The magnetocrystalline anisotropy energies are calculated using the linear muffin-tin orbital (LMTO) method in the atomic sphere approximation (ASA) including spin-orbit interaction and orbital polarization. The force-theorem is used to express the total energy difference (between the two directions of magnetization) as a difference in the sum of the single particle eigenvalues. We find that it is possible to predict the correct easy-axis for YCo5 and YFe5. Secondly it is found that the inclusion of orbital polarization is essential for the cobalt compound but less important for the iron compound. The different contributions from the two inequivalent transition metal sites to the anisotropy energy and orbital magnetization are discussed.

Ground State Properties of the Ai-Ti System

1990 ◽  
Vol 186 ◽  
Author(s):  
Prabhakar P. Singh ◽  
Mark Asta ◽  
Didier deFontaine ◽  
Mark van Schilfgaarde
Keyword(s):  
Ground State ◽  
Complete Agreement ◽  
Full Potential ◽  
Atomic Sphere ◽  
Lattice Constants ◽  
Ground State Properties ◽  
Lmto Method ◽  
Sphere Approximation ◽  
Atomic Sphere Approximation ◽  
Low Symmetry

AbstractGround state structural energies and lattice constants of Al-Ti system have been studied using the linear muffin-tin orbital (LMTO) method. In particular, we examine the effects of various approximations for the potential on the structural energies of low-symmetry compounds such as Al3Ti. In order to stabilize Al3Ti, in the atomic sphere approximation, the Muffin-Tin correction is essential although the resulting c/a is 10% too large. The lattice constants calculated with the full-potential LMTO method are in complete agreement with experiments, indicating the importance of non-sphericity of the potential for low-symmetry systems.

First principle study of the electronic properties of the magnetocaloric compound Gd5Si4

2014 ◽  
Vol 28 (13) ◽  
pp. 1450103 ◽  
Author(s):  
Zobeideh Momeni Larimi ◽  
Ahmad Amirabadizadeh ◽  
Ahmad Yazdani ◽  
Hadi Arabi
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Structural Parameters ◽  
Magnetic Moments ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
Functional Theory ◽  
Lattice Constants ◽  
Effective Role ◽  
Linearized Augmented Plane Wave

The electronic structure and magnetic properties of the Gd 5 Si 4 compound have been investigated by the first principles full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT) using the WIEN2k code. The Coulomb corrected local-spin density approximation (LSDA + U) in the self-interaction correction (SIC) has been used for the exchange-correlation potential. Based on the calculated results, the ground state of Gd 5 Si 4 is found to be ferromagnetic (FM). The optimized structural parameters and magnetic properties including the lattice constants and magnetic moments are in good agreement with experimental data. The magnetic moments of the Gd atoms in Gd 5 Si 4 are smaller than that of the elemental gadolinium. The magnetic moment of Gd 5 Si 4 is found to be 37.8 μB/f.u. DOS results show that the magnetic properties of the compound depend on the hybridization between Si -3p and Gd -5d states which have an effective role in the RKKY interaction. The existence of the very flat bands at -7 eV for spin up and at +3 eV for spin down that is mainly Gd -4f characters shows that the LSDA + U method provides the better description of our systems. The obvious overlap of electron densities between the Gd1 and Si atoms indicates a covalent-like bonding between them.

MAGNETIC MOMENTS NEAR THE SHARP INTERFACES OF FERROMAGNETIC MATERIALS

2002 ◽  
Vol 16 (24) ◽  
pp. 3655-3669 ◽  
Author(s):  
ŽELJKO V. ŠLJIVANČANIN ◽  
FILIP R. VUKAJLOVIĆ
Keyword(s):  
Theoretical Calculations ◽  
Magnetic Moments ◽  
Tight Binding ◽  
Function Technique ◽  
Local Spin Density Approximation ◽  
Ferromagnetic Transition ◽  
Hyperfine Fields ◽  
Lmto Method ◽  
Structural Deformations ◽  
Sphere Approximation

Ab initio theoretical calculations of magnetic moments near the interfaces of 3d ferromagnetic transition metals were performed using the self-consistent interface Green's function technique based on linear-muffin-tin orbitals (LMTO) method within the tight-binding (TB) and atomic sphere approximation together with local-spin-density approximation. We have also made supercell spin-polarized (SP) band structure calculations of (1 0 0) Fe/Co interface in the framework of TB-LMTO method, in order to take into account structural deformations and estimate their influence on the magnetic moments near that interface. Our results for layer magnetic moments near Fe/Co, Fe/Ni and Ni/Co interfaces did not show any oscillating behavior, contrary to the recent findings for the magnetic moment profile near Fe/Co interface deduced from the perturbed angular correlation measurements of hyperfine fields. The reasons for this disagreement have been discussed and a comparison with earlier experimental and theoretical results was made.

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