Spin-Polarized Density of States and Electron Tunnelling from the CO/Al2O3 Interface

1997 ◽  
Vol 492 ◽  
Author(s):  
D. Nguyen-Manh ◽  
E.Yu. Tsymbal ◽  
D. G. Pettifor ◽  
C. Arcangeli ◽  
R. Tank ◽  
...  
Keyword(s):  
Spin Polarization ◽  
Density Of States ◽  
Fermi Energy ◽  
Electron Tunneling ◽  
Band Structure Calculations ◽  
Minority Spin ◽  
Spin Polarized ◽  
Structure Calculations ◽  
Tunnelling Current ◽  
Majority Spin

ABSTRACTIn order to elucidate the mechanism of spin-polarized electron tunneling in thin-film ferromagnet-insulator junctions, self-consistent band structure calculations of the CO/Al2O3 interface have been performed using a new LMTO technique. Since the results of the calculations are very sensitive to the distance between the Co and Al planes, we have minimised the total energy with respect to this distance. Our calculations show that at the Fermi energy a strong bonding between the 3d-electrons of Co with the sp-electrons of Al at the interface can have an important influence on the spin polarization of the layer-projected density of states (LPDOS) of inner Al and O layers. Since the Fermi energy lies within the minority-spin d-band of Co but above the majority-spin d-band, the sp-d bonding results in a smaller LPDOS of the minority-spin electrons of the interfacial Al layers in comparison to that of the majority-spin electrons. This asymmetry in the LPDOS extends to the inner Al2O3 layers implying a positive spin polarization of the tunneling density of states. The result is consistent with experimental observations on tunnelling from cobalt through alumina where positive values of the spin polarization of the tunnelling current were measured.

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.

The Spin Transport of the Coblt Dimers with Different Directions

2014 ◽  
Vol 543-547 ◽  
pp. 3947-3950
Author(s):  
Shi Wei Ren
Keyword(s):  
Transport Properties ◽  
Spin Polarization ◽  
Density Of States ◽  
Bias Voltage ◽  
Spin Transport ◽  
First Principle ◽  
Transport Direction ◽  
Spin Polarized ◽  
Analysis Calculation

In this paper, the spin transport properties of the coblt dimers parrallel to the transport direction and perpendicular to ransprot direction are investigated by using the first principle analysis. Calculation shows that both the coblt dimers parrallel to the transport direction and perpendicular to ransprot direction give obvious spin polarized density of states and current. It is found that the dimer parrallel to the transport direction have larger spin polarization current.The spin polarized efficiency for the parrallel dimer increase steadily with the increase of the bias voltage. But the the spin polarization for the transverse dimer changes greatly.

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 electronic structure of disordered system

1964 ◽  
Vol 279 (1376) ◽  
pp. 82-97 ◽  
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Density Of States ◽  
Disordered System ◽  
Perfect Lattice ◽  
Geometric Approximation ◽  
Band Structure Calculations ◽  
Interacting Electrons ◽  
Simplifying Assumptions ◽  
Structure Calculations

A general expression is written down for the density of states of non-interacting electrons in a disordered system. The expression is obtained on the basis of two simplifying assumptions; the geometric approximation, which is connected with the disorder, and an approximation concerning the potential which is commonly used in band structure calculations. In the case of a perfect lattice the result of Kohn & Rostoker (1954) for the band structure of the lattice is derived, and details of the density of states are available from the formula thus obtained. It is shown how the change in the energy of the electrons due to the presence of a phonon can be obtained.

Spin Polarized Transport through Structures Consist of the Ferromagnetic Semiconductor in Presence of a Inhomogeneous Magnetic Field

2011 ◽  
Vol 194-196 ◽  
pp. 679-682
Author(s):  
Zahra Bamshad
Keyword(s):  
Magnetic Field ◽  
Spin Polarization ◽  
Fermi Energy ◽  
Magnetic Tunnel Junction ◽  
Inhomogeneous Magnetic Field ◽  
Spin Polarized ◽  
Polarized Transport ◽  
Dimensional Electron Gas ◽  
Spin Electronic ◽  
Spin Polarized Transport

The spin-polarized transport is investigated in a magnetic tunnel junction which consists of two ferromagnetic electrodes separated by a magnetic barrier and a nonmagnetic metallic spacer placed in distance above the two dimensional electron gas (2DEG) in presence of an inhomogeneous external modulated magnetic field and a perpendicular wave vector dependent effective potential. Based on the transfer matrix method and the nearly-free-electron approximation the dependence of the conductance and spin polarization on the Fermi energy of the electrons are studied theoretically the. strong oscillations with large amplitude investigated in spin polarization in terms of the Fermi energy due to the inhomogeneous magnetic field. The conductance in terms of the Fermi energy shows no oscillation in low energy but has a strong pick in middle region. this results may be useful for the development of spin electronic devices based on coherent transport, or may be used as a tunable spin-filter.

STUDY OF ELECTRONIC STRUCTURE OF MgB2 BY MULTIPLE-SCATTERING CALCULATIONS OF B K-EDGE XANES

2002 ◽  
Vol 16 (11n12) ◽  
pp. 1605-1612
Author(s):  
ZIYU WU ◽  
N. L. SAINI ◽  
A. BIANCONI
Keyword(s):  
Multiple Scattering ◽  
Density Of States ◽  
Core Hole ◽  
Edge Structure ◽  
X Ray ◽  
The Core ◽  
Al Substitution ◽  
Band Structure Calculations ◽  
X Ray Absorption ◽  
Structure Calculations

The MgB 2 system is studied by self consistent multiple-scattering calculations at the B K-edge X-ray absorption near edge structure (XANES). We find that the features in the B K-edge XANES are strongly affected by medium and long range order with large influence of the core hole potential suggesting that the band structure calculations are not enough to provide a quantitative interpretation of the spectral features. We have investigated evolution of density of states in the conduction band as a function of Al substitution in place of the Mg. The results are consistent with the fact that the Al substitution influences mainly the density of states in the B σ-band and hence suppresses the superconductivity.

Spin Polarized Photoemission from Fe On CU(100)

1991 ◽  
Vol 231 ◽  
Author(s):  
D.P. Pappas ◽  
K.-P. KÄmper ◽  
B.P. Miller ◽  
H. Hopster ◽  
D.E. Fowler ◽  
...  
Keyword(s):  
Low Energy ◽  
Photoemission Spectroscopy ◽  
Universal Curve ◽  
Exchange Splitting ◽  
Attenuation Length ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Minority Spin ◽  
Spin Polarized ◽  
The Difference ◽  
Majority Spin

AbstractThe spin resolved electronic structure of ultra-thin Fe films on Cu(100) was investigated using spin polarized angle resolved photoemission spectroscopy. All exchange splitting of the Fe ∆s band of 2.5 eV is observed for photon energies between 20 and 30 eV. ∆ peak at 6 eV binding energy which has been previously identified as a many-electron resonance was observed only after contamination of the films with oxygen. In addition, the spin dependent attenuation lengths for electrons in Fe were measured at 11, 19, and 40 eV above Ef. The attenuation length for the minority spin electrons was found to be shorter than that of the majority spin electrons. The difference between the two attenuation lengths was shown to increase at low energy. Short attenuation lengths of ≃3 monolayer were measured at II eV. The large increase of the attenuation length at low energy which is expected from the “universal curve” is not observed in Fe.

Spin Polarized Tunneling at the Metal-Insulator Transition

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3723-3725 ◽  
Author(s):  
W. Teizer ◽  
F. Hellman ◽  
R. C. Dynes
Keyword(s):  
Spin Polarization ◽  
Density Of States ◽  
Insulator Transition ◽  
Critical Regime ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Spin Polarized ◽  
Quantum Critical ◽  
Spin Polarized Tunneling

We have determined the spin polarized density of states (DOS) of 3-d amorphous Gd x Si 1-x in the quantum critical regime of a tunable Metal-Insulator Transition (MIT). Using a spin polarized BCS DOS we fit the data and extract the spin polarization P.

Sign in / Sign up

Export Citation Format

Share Document