scholarly journals Origin of the Low Magnetic Moment in Fe2AlTi: An Ab Initio Study

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1732 ◽  
Author(s):  
Martin Friák ◽  
Anton Slávik ◽  
Ivana Miháliková ◽  
David Holec ◽  
Monika Všianská ◽  
...  
Keyword(s):  
Ab Initio ◽  
Magnetic Moment ◽  
Energy Surface ◽  
Magnetic Moments ◽  
Local Magnetic Moment ◽  
Spin Configuration ◽  
Spin Effects ◽  
Order Of Magnitude ◽  
Huge Impact ◽  
Insight Into

The intermetallic compound Fe 2 AlTi (alternatively Fe 2 TiAl) is an important phase in the ternary Fe-Al-Ti phase diagram. Previous theoretical studies showed a large discrepancy of approximately an order of magnitude between the ab initio computed magnetic moments and the experimentally measured ones. To unravel the source of this discrepancy, we analyze how various mechanisms present in realistic materials such as residual strain effects or deviations from stoichiometry affect magnetism. Since in spin-unconstrained calculations the system always evolves to the spin configuration which represents a local or global minimum in the total energy surface, finite temperature spin effects are not well described. We therefore turn the investigation around and use constrained spin calculations, fixing the global magnetic moment. This approach provides direct insight into local and global energy minima (reflecting metastable and stable spin phases) as well as the curvature of the energy surface, which correlates with the magnetic entropy and thus the magnetic configuration space accessible at finite temperatures. Based on this approach, we show that deviations from stoichiometry have a huge impact on the local magnetic moment and can explain the experimentally observed low magnetic moments.

scholarly journals Unveiling orbital coupling at the CoPc/Bi(111) surface by ab initio calculations and photoemission spectroscopy

RSC Advances ◽  
2017 ◽  
Vol 7 (82) ◽  
pp. 52143-52150
Author(s):  
Zhaofeng Liang ◽  
Haoliang Sun ◽  
Kongchao Shen ◽  
Jinbang Hu ◽  
Bo Song ◽  
...  
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Magnetic Moment ◽  
Local Magnetic Moment ◽  
Photoemission Spectroscopy

Orbital coupling is revealed at the CoPc/Bi(111) interface with the local magnetic moment retained in CoPc.

FORMATION OF MAGNETIC MOMENTS IN INTERMETALLIC COMPOUNDS AND ALLOYS

1993 ◽  
Vol 07 (01n03) ◽  
pp. 756-759 ◽  
Author(s):  
T. BEUERLE ◽  
K. HUMMLER ◽  
M. FÄHNLE
Keyword(s):  
Transition Metals ◽  
Ab Initio ◽  
Intermetallic Compounds ◽  
Magnetic Moment ◽  
Nearest Neighbor ◽  
Physical Mechanism ◽  
Magnetic Moments ◽  
Lmto Method ◽  
Minimum Number ◽  
Alloy Systems

Jaccarino and Walker proposed that in certain alloy systems a considered kind of atom attains a constant value of the magnetic moment if it is surrounded by at least a minimum number of nearest-neighbor atoms of a certain kind, and that it is nonmagnetic otherwise. It is shown by ab initio supercell calculations within the LMTO method that the system Nbi−xMox with 1% iron approximately fulfills the Jaccarino-Walker hypothesis, whereas the alloy FexRh1−x does not. The physical mechanism for the destruction of the Fe moment in bcc alloys with 4d and 5d transition metals is elucidated.

Determination of the magnetic moments of 6Li and 7Li nuclei using an NMR spectrometer that records signals from two nuclei simultaneously

2020 ◽  
pp. 3-8
Author(s):  
Yu. I. Neronov
Keyword(s):  
Experimental Data ◽  
Magnetic Moment ◽  
Theoretical Calculations ◽  
Magnetic Moments ◽  
Systematic Errors ◽  
Simultaneous Recording ◽  
Resonant Frequencies ◽  
Low Concentration ◽  
Order Of Magnitude

The ratio of NMR frequencies of lithium isotopes was determined: with an error of 4,9·10–10. We used a spectrometer mode with simultaneous recording of signals from two cores, which allows us to reduce random and systematic errors by an order of magnitude. The ratio of the resonant frequencies of water protons and 7Li ions was determined: with an error of 3,5·10–9 for solutions with an extremely low concentration of LiOH*H2O salt in water and at a temperature of 25 °C. Based on the data obtained, the magnetic moments of lithium nuclei were calculated. The known data on the magnetic moment of the proton and data on the electronic shielding of these nuclei were used. The comparison of experimental data on µ(6Li) and µ(7Li) with data from theoretical calculations is discussed.

AB INITIO ELECTRONIC STRUCTURE CALCULATIONS OF HALF-METALLIC FERROMAGNETISM IN CALCIUM CHALCOGENIDES DOPED WITH B, C AND N

2011 ◽  
Vol 25 (18) ◽  
pp. 1537-1548 ◽  
Author(s):  
M. YOGESWARI ◽  
G. KALAPANA
Keyword(s):  
Ab Initio ◽  
Magnetic Moment ◽  
Local Density ◽  
Magnetic Moments ◽  
Electronic Band ◽  
Half Metallic ◽  
N Doping ◽  
C And N ◽  
Metallic Ferromagnetism ◽  
Half Metallic Ferromagnetism

Self-consistent ab initio calculations were carried out to study the structural, electronic and magnetic properties of nine ternary compounds Ca 4 XA 3 ( X = B , C and N ; A = S , Se and Te ). The calculations were performed by using tight-binding linear muffin tin orbital (TB-LMTO) method within the local density approximation (LDA). The calculations reveal that half-metallic ferromagnetism can be obtained for C - and N -doping with the integer magnetic moment of 2.00 μ B and 1.00 μ B per cell. However, B substitution does not induce magnetism in CaS and CaSe systems, but it produces ferromagnetism in CaTe system with magnetic moment of 2.67 μ B per cell. Moreover C - and N -doping enhance the stable ferromagnetic state in calcium chalcogenide systems. Spin-dependent electronic band structure, total and partial densities of state calculations demonstrate that localized magnetic moments substantially come from impurity atoms. Half-metallic ferromagnetism predominately originates from spin-polarization of electrons in 2p orbital states of C and N atoms. In addition, equilibrium lattice constant, bulk modulus, atomic local magnetic moments, half-metallic gap and robustness of half-metallicity have been calculated.

Insight into the magnetic moment of iron borides: theoretical consideration from the local coordinative and electronic environment

2020 ◽  
Vol 49 (7) ◽  
pp. 2168-2175 ◽  
Author(s):  
Hongliu Wan ◽  
Xing-Wu Liu ◽  
Ming Qing ◽  
Jin-Jia Liu ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Magnetic Moment ◽  
Theoretical Consideration ◽  
Local Magnetic Moment ◽  
Bond Valence ◽  
Orbital Energy ◽  
Electronic Environment ◽  
Linear Relationships ◽  
Insight Into

Linear relationships between the local magnetic moment of iron borides and the bond valence as well as the orbital energy were disclosed.

scholarly journals MAJORANA NEUTRINO MAGNETIC MOMENTS

2006 ◽  
Vol 15 (02) ◽  
pp. 441-445 ◽  
Author(s):  
MAREK GÓŹDŹ ◽  
WIESŁAW A. KAMIŃSKI ◽  
FEDOR ŠIMKOVIC
Keyword(s):  
Magnetic Moment ◽  
Magnetic Moments ◽  
Majorana Neutrino ◽  
Order Of Magnitude

The presence of trilinear R-parity violating interactions in the MSSM lagrangian leads to existence of quark–squark and lepton–slepton loops which generate mass of the neutrino. By introducing interaction with an external photon the magnetic moment is obtained. We derive bounds on that quantity being around one order of magnitude stronger than those present in the literature.

THE FIRST PRINCIPLES CALCULATION OF STRUCTURAL, ELECTRONIC AND MAGNETIC PROPERTIES OF MnXY (X = Ru, Rh AND Y = Ga, Ge, Sb) ALLOYS

2011 ◽  
Vol 25 (26) ◽  
pp. 2079-2090 ◽  
Author(s):  
S. M. MONIRI ◽  
Z. NOURBAKHSH ◽  
M. MOSTAJABODAAVATI
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moment ◽  
Density Functional ◽  
Magnetic Moments ◽  
Heusler Alloys ◽  
Local Magnetic Moment ◽  
First Principles Calculation ◽  
Functional Theory ◽  
Half Metallic ◽  
Electronic And Magnetic Properties

The structural, electronic and magnetic properties of MnXY ( X = Ru , Rh and Y = Ga , Ge , Sb ) Heusler alloys are studied using density functional theory by the WIEN2k package. These materials are ferromagnetic. Also they have some interesting half-metallic properties. The electron density of states, total and local magnetic moment of these alloys are calculated. We have calculated the effective Coulomb interaction U eff using the ab initio method. We have compared the magnetic moments of these alloys in GGA and LDA + U with the Slater–Pauling rule. Furthermore the effect of hydrostatic pressure on the magnetic moment of these alloys is studied. The calculated results are fitted with a second order polynomial.

scholarly journals NEUTRALINO INDUCED MAJORANA NEUTRINO TRANSITION MAGNETIC MOMENTS

2009 ◽  
Vol 18 (04) ◽  
pp. 1094-1098 ◽  
Author(s):  
MAREK GÓŹDŹ ◽  
WIESŁAW A. KAMIŃSKI
Keyword(s):  
Magnetic Moment ◽  
Magnetic Moments ◽  
Majorana Neutrino ◽  
Neutrino Magnetic Moment ◽  
Order Of Magnitude

We calculate the effect of neutrino-neutralino mixing on the neutrino magnetic moment and compare it with the contribution of pure particle-sparticle loop. We have found that the dominated mechanism is still the bare loop, and that the bilinear insertions on the external neutrino lines contribute at least one order of magnitude weaker.

Sign in / Sign up

Export Citation Format

Share Document