Detailed analysis of magnetism in Ru monolayers

2004 ◽  
Vol 82 (9) ◽  
pp. 717-729 ◽  
Author(s):  
L M García-Cruz ◽  
A Rubio-Ponce ◽  
A E García ◽  
R Baquero
Keyword(s):  
Density Of States ◽  
Magnetic Moment ◽  
Ground State ◽  
Electronic States ◽  
Magnetic Behavior ◽  
Nearest Neighbors ◽  
Lattice Parameter ◽  
Magnetic Activity ◽  
First Impression ◽  
The One

We study the magnetic behavior of a 4d transition-metal Ru monolayer (ML) on different substrates and orientations. In the ground state, an ideal Ru-ML is expected to be ferromagnetic on Ag(001) and Au(001) with a magnetic moment, µ, around 1.7 µB (Bohr magnetons) in both cases. On Cu(001), a Ru-ML is not magnetic. In this paper, we study the magnetic behavior of a Ru-ML at other orientations, i.e., (110) and (111), and analyze the phenomenon as a whole. We find magnetism on Au(111), and Ag(111) (µ ≈ 1 µB for both) but no magnetic activity on a Cu substrate in any orientation. This gives the first impression that the lattice parameter of the substrate is the one that governs the switching on of magnetism in the Ru-ML. But then, we find that on both Ag(110) and Au(110), an ideal Ru-ML is not magnetic. For that reason, we have tried to find another geometric parameter that would correlate better with the magnetic moment. We find that neither the total number of first nearest neighbors for each orientation, nor the number of them on the ML, or the number of them in the substrate, or the area per atom on the ML, correlate. We find a correlation with a parameter, Ω0, that represents the volume per atom in the monolayer–substrate interface region. But this parameter seems to have the wrong trend according to intuition. Further analysis shows that the details of the interaction are important, and that the physics underlying the switching on of magnetism in a Ru-ML on noble metal substrates, is determined by an intraband transfer of d-electronic states, from lower and higher energies to the Fermi level, that enhances the density of states at that energy, in an important way. This depends on specificities of the interaction between the ML and the substrate that are hardly taken into account by a single parameter that is merely geometric. PACS Nos.: 75.10–b, 75.30–m, 75.70.Ak, 73.20.At

Magnetic and Electronic Properties of the Compound Y(Co,Fe)5 Calculated by the Augmented Spherical Wave Method

2009 ◽  
Vol 68 ◽  
pp. 145-151
Author(s):  
María Cristina Grijalva Castillo ◽  
José Andrés Matutes-Aquino
Keyword(s):  
Band Structure ◽  
Density Of States ◽  
Magnetic Moment ◽  
Spherical Wave ◽  
Magnetic Behavior ◽  
Energy Band Structure ◽  
Unit Cell ◽  
Positive Pressure ◽  
Wave Method ◽  
Soft Ferromagnetic

Energy band structure and density of states of the compound Y(Co,Fe)5 were obtained by the augmented spherical wave method. Also the localization of the magnetic moment inside the unit cell, the effect of pressure and the substitution of Co atoms by Fe atoms were studied at the temperature of 0 K. Metallic Co showed a magnetic moment of 1.5 B while metallic Y showed its non magnetic behavior. Inside the compound YCo5 the Y atom had a contribution of –0.3 B to the total magnetization of the unit cell. A negative pressure caused the change of the Fermi energy and the modification of the magnetic moment. With a big enough positive pressure the total magnetic moment dropped to zero. The substitution of Co by Fe caused a change in the compound from strong ferromagnetic to soft ferromagnetic.

ROTATIONAL ANALYSIS OF THE β BANDS OF PHOSPHORUS MONOXIDE

1959 ◽  
Vol 37 (2) ◽  
pp. 136-143 ◽  
Author(s):  
Nand Lal Singh
Keyword(s):  
Ground State ◽  
Band System ◽  
Electronic States ◽  
Rotational Analysis ◽  
Rotational Constants ◽  
Fine Structures ◽  
Π State

The fine structures of three of the β bands of PO which occur near 3200 Å have been analyzed. The analysis shows that the upper state of this band system is a 2Σ and not a 2Π state as previously believed. The rotational constants of both electronic states have been determined and it is found that the ground state constants, previously determined from the γ bands, are incorrect.

scholarly journals Two-term expansion of the ground state one-body density matrix of a mean-field Bose gas

2021 ◽  
Vol 60 (3) ◽  
Author(s):  
Phan Thành Nam ◽  
Marcin Napiórkowski
Keyword(s):  
Density Matrix ◽  
Ground State ◽  
Mean Field ◽  
Interaction Strength ◽  
Bose Gas ◽  
Body Density ◽  
The Mean ◽  
The One ◽  
Mean Field Regime ◽  
Number Of Particles

AbstractWe consider the homogeneous Bose gas on a unit torus in the mean-field regime when the interaction strength is proportional to the inverse of the particle number. In the limit when the number of particles becomes large, we derive a two-term expansion of the one-body density matrix of the ground state. The proof is based on a cubic correction to Bogoliubov’s approximation of the ground state energy and the ground state.

MAGNETIC BEHAVIOR OF IRON IONS IN THE P2O5·CaO GLASS MATRIX

2003 ◽  
Vol 17 (24) ◽  
pp. 1271-1275 ◽  
Author(s):  
I. ARDELEAN ◽  
C. ANDRONACHE ◽  
P. PǍŞCUŢǍ
Keyword(s):  
Magnetic Susceptibility ◽  
High Temperature ◽  
Magnetic Moment ◽  
Glass Matrix ◽  
Magnetic Behavior ◽  
Iron Ions ◽  
Ion Content ◽  
Dipole Interactions ◽  
Valence States ◽  
Temperature Susceptibility

The temperature dependence of the magnetic susceptibility of x Fe 2 O 3·(100-x)-[ P 2 O 5· CaO ] glasses with 0<x≤50 mol % have been investigated. These data revealed that the valence states and the distribution of iron ions in the glass matrix depend on the Fe 2 O 3 content. For the glasses with x≤1 mol % only Fe 3+ ions are evidenced. In the case of the glasses with 3≤x≤35 mol % both Fe 3+ and Fe 2 ions co-exist in the P 2 O 5· CaO glass matrix, the Fe 2+ ion content is higher than that of the Fe 3+ ions for glasses with x≥10 mol %. For the glasses with x>35 mol %, the evaluated values of the μ eff indicate either the presence of Fe + ions or the coordination influence on the magnetic moment of iron ions, but the presence of small quantities of the antiferromagnetic or ferrimagnetic interactions between iron ions in studied temperature range cannot be excluded. The high temperature susceptibility results indicate that the iron ions are isolated or participate in dipole-dipole interactions for glasses with x≤35 mol % and are antiferromagnetically coupled for higher contents of Fe 2 O 3.

The Energy Band Structure of Polyacene with Soliton Excitation

1997 ◽  
Vol 11 (11) ◽  
pp. 477-483 ◽  
Author(s):  
Z. J. Li ◽  
H. B. Xu ◽  
K. L. Yao
Keyword(s):  
Band Structure ◽  
Charge Density ◽  
Energy Band ◽  
Energy Gap ◽  
Electronic States ◽  
Energy Band Structure ◽  
Energy Spectra ◽  
Energy Band Gap ◽  
The One ◽  
Soliton Excitation

Starting from the extensional Su–Schrieffer–Heeger model taking into account the effects of interchain coupling, we have studied the energy spectra and electronic states of soliton excitation in polyacene. The dimerized displacement u0 is found to be similar to the case of trans-polyacetylene, and equals to 0.04 Å. The energy-band gap is 0.38 eV, in agreement with the results derived by other authors. Two new bound electronic states have been found in the conduction band and in the valence band, which is different from the one of trans-polyacetylene. There exists two degenerate soliton states in the center of energy gap. Furthermore, the distribution of charge density and spin density have been discussed in detail.

VUV FRAGMENTATION OF SOME HYDROFLUOROCARBON CATIONS STUDIED USING COINCIDENCE TECHNIQUES

2002 ◽  
Vol 09 (01) ◽  
pp. 153-158 ◽  
Author(s):  
WEIDONG ZHOU ◽  
D. P. SECCOMBE ◽  
R. Y. L. CHIM ◽  
R. P. TUCKETT
Keyword(s):  
Kinetic Energy ◽  
Ab Initio ◽  
Ground State ◽  
Lower Energy ◽  
Lone Pair ◽  
Electronic States ◽  
Photoelectron Spectra ◽  
Highest Occupied Molecular Orbital ◽  
Impulsive Model ◽  
Lone Pair Electrons

Threshold photoelectron–photoion coincidence (TPEPICO) spectroscopy has been used to investigate the decay dynamics of the valence electronic states of the parent cation of several hydrofluorocarbons (HFC), based on fluorine-substituted ethane, in the energy range 11–25 eV. We present data for CF 3– CHF 2, CF 3– CH 2 F , CF 3– CH 3 and CHF 2– CH 3. The threshold photoelectron spectra (TPES) of these molecules show a common feature of a broad, relatively weak ground state, associated with electron removal from the highest-occupied molecular orbital (HOMO) having mainly C–C σ-bonding character. Adiabatic and vertical ionisation energies for the HOMO of the four HFCs are presented, together with corresponding values from ab initio calculations. For those lower-energy molecular orbitals associated with non-bonding fluorine 2pπ lone pair electrons, these electronic states of the HFC cation decay impulsively by C–F bond fission with considerable release of translational kinetic energy. Appearance energies are presented for formation of the daughter cation formed by such a process (e.g. CF 3– CHF +), together with ab initio energies of the corresponding dissociation channel (e.g. CF 3– CHF + + F ). Values for the translational kinetic energy released are compared with the predictions of a pure-impulsive model.

Magnetic moment and electric quadrupole moment of the N ground state

1999 ◽  
Vol 451 (1-2) ◽  
pp. 11-18 ◽  
Author(s):  
H. Ogawa ◽  
K. Asahi ◽  
K. Sakai ◽  
A. Yoshimi ◽  
M. Tsuda ◽  
...  
Keyword(s):  
Quadrupole Moment ◽  
Magnetic Moment ◽  
Ground State ◽  
Electric Quadrupole ◽  
Electric Quadrupole Moment

THE GROUND-STATE PHASE DIAGRAMS OF THE SPIN-2 ISING MODEL

2007 ◽  
Vol 21 (31) ◽  
pp. 5265-5274 ◽  
Author(s):  
AHMET ERDİNÇ
Keyword(s):  
Magnetic Field ◽  
Ising Model ◽  
External Magnetic Field ◽  
Phase Diagrams ◽  
Crystal Field ◽  
Ground State ◽  
Exchange Interactions ◽  
Nearest Neighbors ◽  
Biquadratic Exchange ◽  
Model Hamiltonian

The ground-state phase diagrams are obtained for the spin-2 Ising model Hamiltonian with bilinear and biquadratic exchange interactions and a single-ion crystal field. The interactions are assumed to be only between nearest-neighbors. Obtained phase diagrams are presented in the (Δ,J), (K,J), (Δ/J,K/J), (Δ/|J|,K/|J|), (Δ/|K|,J/|K|), (H/J,Δ/J), (H/|J|,Δ/|J|), (H/J,K/J), and (H/|J|,K/|J|) planes where J, K, Δ, and H are the bilinear, biquadratic exchange interactions, the single-ion crystal field, and the external magnetic field, respectively. The influence of the external magnetic field on the spin configurations is investigated.

scholarly journals 4. On a Thermomagnetic Thermoscope

1880 ◽  
Vol 10 ◽  
pp. 538-539
Author(s):  
W. Thomson
Keyword(s):  
Magnetic Moment ◽  
Horizontal Plane ◽  
Hardened Steel ◽  
The Other ◽  
Silk Fibre ◽  
Steel Wires ◽  
The One

This thermoscope is founded on the change produced in the magnetic moment of a steel magnet by change of temperature. Several different forms suggest themselves: the one which seems best adapted to give good results is to be made as follows:—(1.) Prepare an approximately astatic system of two thin, hardened steel wires, r b, r′ b′, each 1 cm. long, one of them, r, b, hung by a single silk fibre, and the other hung bifilarly from it, by fibres about 3 cms. long, so attached that the projections of the two, on a horizontal plane, shall be inclined at an angle of about ·01 of a radian (or ·57°) to one another.

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