ELECTRONIC AND MAGNETIC STUCTURE OF HEXAGONAL FeGe

1993 ◽  
Vol 07 (01n03) ◽  
pp. 1023-1026 ◽  
Author(s):  
ANDERS HJELM
Keyword(s):  
Spin Structure ◽  
Band Structure Calculations ◽  
Easy Direction ◽  
Spin Polarized ◽  
Unit Cells ◽  
Half Angle ◽  
Experimental Values ◽  
Antiferromagnetic Spin ◽  
Structure Calculations ◽  
Good Agreement

Al low temperatures hexagonal FeGe (B 35) exhibits a double—cone antiferromagnetic spin structure. In the present work spin polarized, self consistent band structure calculations are presented for one (ferromagnetic) and two (antiferromagnetic) unit cells. The calculated sublattice magnetization along the c axis, 1.47 μB/Fe atom, is smaller than the experimental values, 1.53–1.78 μB/Fe atom. It is also shown that the easy direction deviates from the c axis, and the cone half angle is estimated to be 12°, in good agreement with the experimental value of 14°.

The temperature dependence of the resistivity of ferromagnetic metals

1961 ◽  
Vol 263 (1315) ◽  
pp. 473-482 ◽  
Keyword(s):  
Band Structure ◽  
Temperature Dependence ◽  
Fourth Power ◽  
Fractional Change ◽  
Ferromagnetic Metals ◽  
Band Structure Calculations ◽  
Structure Calculations ◽  
Good Agreement

The temperature dependence of the resistivity of nickel and gadolinium has been measured. For nickel, the results are in good agreement with the band-structure calculations of Fletcher (1952); for gadolinium the fractional change in resistivity is almost exactly equal to the fourth power of the reduced magnetization.

Magnetism in 4d Transition Metal–Ag(001) Sandwiches

1991 ◽  
Vol 231 ◽  
Author(s):  
Dennis P. Clougherty ◽  
M. E. Mchenry ◽  
J. M. Maclaren
Keyword(s):  
Transition Metal ◽  
Band Structure ◽  
Ground State ◽  
Fermi Energy ◽  
Band Structure Calculations ◽  
Spin Polarized ◽  
Densities Of States ◽  
Ferromagnetic Ground State ◽  
Sandwich Configuration ◽  
Structure Calculations

AbstractUsing ab-initio spin-polarized layer Korringa-Kohn-Rostoker (LKKR) band structure calculations, we investigated the possibility of having a stable ferromagnetic ground state in 4d transition metal (TM)–Ag(001) sandwiches (TM = Tc, Ru, Rh, and Pd). In contrast to recent calculations performed on systems with TM overlayers on Ag (001), we find that the TM sandwich configuration gives a paramagnetic ground state. While excellent agreement in general is obtained for the layer-projected densities of states (LDOS), the sandwich configuration lowers the densities of states at the Fermi energy (EF) in the case of Rh and Ru by a small amount which seemingly prevents the marginal ferromagnetic instability predicted by Eriksson et. al. (Phys. Rev. Lett. 66, 1350 (1991)) from occurring.

scholarly journals Equation of state of condensed matter in laser-induced high-pressure regime

2003 ◽  
Vol 21 (4) ◽  
pp. 523-528 ◽  
Author(s):  
B.K. GODWAL ◽  
R.S. RAO ◽  
A.K. VERMA ◽  
M. SHUKLA ◽  
H.C. PANT ◽  
...  
Keyword(s):  
Band Structure ◽  
Condensed Matter ◽  
Ambient Pressure ◽  
Band Structure Calculations ◽  
Temperature Isotherm ◽  
Shock Hugoniot ◽  
Total Energies ◽  
Pressure Regime ◽  
Structure Calculations ◽  
Good Agreement

We have simulated the shock Hugoniot of copper and uranium based on the results of first principles electronic structure calculations. The room temperature isotherm has been obtained by evaluating the accurate ground state total energies at various compressions, and the thermal and electronic excitation contributions were obtained by adopting isotropic models using the results obtained by the band structure calculations. Our calculations ensure smooth consideration of pressure ionization effects as the relevant core states are treated in the semi-core form at the ambient pressure. The pressure variation of the electronic Grüneisen parameter was estimated for copper using the band structure results, which leads to good agreement of the simulated shock Hugoniot with the measured shock data. The simulation results obtained for U are also compared with the experimental data available in literature and with our own data.

Investigation of the effects of boron on Ni3Al grain boundaries by atomistic simulations

1990 ◽  
Vol 5 (5) ◽  
pp. 955-970 ◽  
Author(s):  
S.P. Chen ◽  
A.F. Voter ◽  
R.C. Albers ◽  
A.M. Boring ◽  
P.J. Hay
Keyword(s):  
Grain Boundaries ◽  
Electronic Band Structure ◽  
Cohesive Strength ◽  
Atomistic Simulations ◽  
Electronic Band ◽  
Free Surfaces ◽  
Embedded Atom ◽  
Band Structure Calculations ◽  
Structure Calculations ◽  
Good Agreement

A series of simulations has been performed on grain boundaries in Ni and Ni3Al with and without boron doping using embedded atom-style potentials. A new procedure of obtaining “reference” data for boron related properties from electronic band structure calculations has been employed. Good agreement with existing experimental structural and energetic determinations was obtained. Boron is found to segregate more strongly to grain boundaries than to free surfaces. Adding boron to grain boundaries in Ni and Ni3Al increases their cohesive strength and the work required to pull apart the boundary. This effect is much more dramatic for Ni-rich boundaries than for stoichiometric or Al-rich boundaries. In some Ni-rich cases, adding boron increases the cohesive strength of the boundary to such an extent that the boundaries become stronger than the bulk. Bulk Ni3Al samples that are Ni-rich produce Ni-rich grain boundaries. The best cohesive properties of Ni3Al grain boundaries are obtained when the boundary is Ni saturated and also with boron present. Boron and nickel are found to cosegregate to the grain boundaries.

Atomistic Simulations of Interfaces in Metals and Alloys

1988 ◽  
Vol 141 ◽  
Author(s):  
S. P. Chen
Keyword(s):  
Thin Films ◽  
Electronic Band Structure ◽  
Atomistic Simulations ◽  
Electronic Band ◽  
Free Surfaces ◽  
Segregation Behavior ◽  
Embedded Atom ◽  
Band Structure Calculations ◽  
Structure Calculations ◽  
Good Agreement

AbstractWe have used embedded atom potentials to simulate the surfaces, thin films and grain boundaries in metals (Ni and Al) and alloys (NiAl and Ni3Al). The calculated surface relaxations and ripplings of free surfaces are in good agreement with experiments. A new interference phenomena of interlayer relaxation in thin films are observed in the simulation. The segregation behavior of B and S and their effects on the mechanical properties of Ni3Al are correctly predicted with potentials fitted to data obtained by electronic band structure calculations.

The Fermi surface of beryllium

1964 ◽  
Vol 282 (1391) ◽  
pp. 521-546 ◽  
Keyword(s):  
Band Structure ◽  
Fermi Surface ◽  
Cross Section ◽  
Brillouin Zone ◽  
Field Direction ◽  
Pulsed Magnetic Fields ◽  
Hexagonal Symmetry ◽  
Band Structure Calculations ◽  
Structure Calculations ◽  
Good Agreement

The Fermi surface of beryllium has been determined experimentally by studying the de Haas–van Alphen effect of single crystals in pulsed magnetic fields. The de Haas–van Alphen frequency (proportional to the extremal area of the Fermi surface normal to the field) was measured as a function of field direction. Consideration of the hexagonal symmetry of the Brillouin zone (discussed in the Appendix) shows that only six distinct classes of fre­quency variation with field direction are possible, and these considerations are used to deduce the locations and forms of the various sheets of the Fermi surface. The Fermi surface is found to consist of hole and electron surfaces of equal volume (each containing 0∙162 carrier per atom). The hole surface is somewhat like a coronet, i. e. a ring of six smoothed tetrahedra joined by small necks lying in the central (0001) plane of the first double Brillouin zone, and the electron surface is a set of six roughly ellipsoidal surfaces (cigars) lying on the vertical edges of the second double zone. Detailed shapes and sizes are deduced for the coronet and cigars such that the extremal areas of cross-section are consistent to within 1 % of those obtained from the observed de Haas–van Alphen frequencies. No oscillations of frequency corresponding to the outer (0001) orbit round the coronet were, however, observed; a study of the field dependence of amplitude of the oscillations from the coupled orbit round the cigar shows that this absence can be explained by magnetic breakdown of the {101̄0} band gap. The model described is in good agreement with the predictions of recent band structure calculations, and is consistent with other experimental evidence.

Spin-polarized band-structure calculations for Ni

1979 ◽  
Vol 20 (8) ◽  
pp. 3172-3185 ◽  
Author(s):  
J. R. Anderson ◽  
D. A. Papaconstantopoulos ◽  
L. L. Boyer ◽  
J. E. Schirber
Keyword(s):  
Band Structure ◽  
Band Structure Calculations ◽  
Spin Polarized ◽  
Structure Calculations
Sign in / Sign up

Export Citation Format

Share Document