scholarly journals Thermal Conductivity of Uranium Nitride and Carbide

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
B. Szpunar ◽  
J. A. Szpunar
Keyword(s):  
Thermal Conductivity ◽  
Electronic Structure ◽  
Alternative Fuels ◽  
Magnetic Moments ◽  
Quantitative Agreement ◽  
Uranium Carbide ◽  
Antiferromagnetic Ordering ◽  
Electronic Thermal Conductivity ◽  
Uranium Nitride ◽  
Quantum Espresso

We investigate the electronic thermal conductivity of alternative fuels like uranium nitride and uranium carbide. We evaluate the electronic contribution to the thermal conductivity, by combining first-principles quantum-mechanical calculations with semiclassical correlations. The electronic structure of UN and UC was calculated using Quantum Espresso code. The spin polarized calculations were performed for a ferromagnetic and antiferromagnetic ordering of magnetic moments on uranium lattice and magnetic moment in UC was lower than in UN due to stronger hybridization between 2p electrons of carbon and 5f electrons of uranium. The nonmagnetic electronic structure calculations were used as an input to BolzTrap code that was used to evaluate the electronic thermal conductivity. It is predicted that the thermal conductivity should increase with the temperature increase, but to get a quantitative agreement with the experiment at higher temperatures the interaction of electrons with phonons (and electron-electron scattering) needs to be included.

Magnetic Properties of Embedded Rh Clusters in Ni Matrix

1995 ◽  
Vol 384 ◽  
Author(s):  
Zhi-Qiang Li ◽  
Yuichi Hashi ◽  
Jing-Zhi Yu ◽  
Kaoru Ohno ◽  
Yoshiyuki Kawazoe
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Magnetic Moments ◽  
Functional Formalism ◽  
Rhodium Clusters ◽  
Spin Polarized ◽  
Local Density Functional

ABSTRACTThe electronic structure and magnetic properties of rhodium clusters with sizes of 1 - 43 atoms embedded in the nickel host are studied by the first-principles spin-polarized calculations within the local density functional formalism. Single Rh atom in Ni matrix is found to have magnetic moment of 0.45μB. Rh13 and Rhl 9 clusters in Ni matrix have lower magnetic moments compared with the free ones. The most interesting finding is tha.t Rh43 cluster, which is bulk-like nonmagnetic in vacuum, becomes ferromagnetic when embedded in the nickel host.

Electronic Structure and Transport Properties of La2Zr2O7 Pyrochlore from First Principles

2018 ◽  
Vol 281 ◽  
pp. 767-773
Author(s):  
Zheng Li ◽  
Wei Pan
Keyword(s):  
Thermal Conductivity ◽  
Transport Properties ◽  
Electron Concentration ◽  
Boltzmann Transport ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Electronic Thermal Conductivity ◽  
Transport Calculation ◽  
Scattering Time ◽  
High Temperature Electronic

The first principle calculation as well as the Boltzmann transport calculation have been employed to study the high temperature electronic transport properties of pyrochlore La2Zr2O7. Combing constant scattering time approximation and experiment data, the electronic thermal conductivity and electron concentration are calculated as a function of temperature. The electronic thermal conductivity is 2.6×10-4 W/(m.s) at 1270K and 7.2×10-3 W/(m.s) at 1770K. The electron concentration increase rapidly with when the temperature is above 1600K.

Electronic structure of crystalline uranium nitride: LCAO DFT calculations

2007 ◽  
Vol 48 (S1) ◽  
pp. S125-S133 ◽  
Author(s):  
R. A. Évarestov ◽  
A. I. Panin ◽  
M. V. Losev
Keyword(s):  
Electronic Structure ◽  
Dft Calculations ◽  
Uranium Nitride

scholarly journals Electronic thermal conductivity of disordered metals

2004 ◽  
Vol 70 (15) ◽  
Author(s):  
Roberto Raimondi ◽  
Giorgio Savona ◽  
Peter Schwab ◽  
Thomas Lück
Keyword(s):  
Thermal Conductivity ◽  
Electronic Thermal Conductivity ◽  
Disordered Metals

First principles calculations of intersite disorder influence on the electronic structure and X-ray magnetic circular dichroism in CoFeMnSi Heusler alloy

2020 ◽  
Vol 31 (08) ◽  
pp. 2050109
Author(s):  
S. Uba ◽  
A. Bonda ◽  
L. Uba ◽  
L. V. Bekenov ◽  
V. N. Antonov
Keyword(s):  
Electronic Structure ◽  
Circular Dichroism ◽  
First Principles ◽  
Heusler Alloy ◽  
Magnetic Circular Dichroism ◽  
Magnetic Moments ◽  
X Ray ◽  
The Rich ◽  
X Ray Absorption ◽  
Circular Dichroïsm

Electronic structure, X-ray absorption, and magnetic circular dichroism (XMCD) spectra in the CoFeMnSi Heusler alloy were studied from first principles. Fully relativistic Dirac linear muffin-tin orbital band structure method was implemented with various exchange–correlation functionals tested. The supercell approach was used to study the influence of intersite disorder, at the levels of 6.25%, 12.5%, and 25% within transition metal sites, on the XMCD spectra at [Formula: see text] edges and spin polarization (SP) at the Fermi level. It is found that most sensitive to Fe–Mn and Co–Fe disorder are XMCD spectra at [Formula: see text] edges of Fe, while the sensitivity decreases from Mn to Co. It is shown that magnetic moments estimated with the use of magneto-optical (MO) sum rules agree with the ab initio calculated ones to within [Formula: see text], [Formula: see text], and [Formula: see text], for Co, Fe, and Mn, respectively. The calculated SP decreases from 99% for ordered CoFeMnSi alloy, to 96% upon 25% Co–Fe disorder, to 83% for Fe–Mn disorder, and to 42% in the case of Co–Mn disorder. The calculated spectra agree well with the available experimental data. The rich XMCD spectral structures are predicted from first principles at Fe, Co, Mn and Si [Formula: see text] edges.

Sign in / Sign up

Export Citation Format

Share Document