Thermodynamic Analysis of the Ti-Zr-H Ternary Phase Diagram

2007 ◽  
Vol 26-28 ◽  
pp. 989-992 ◽  
Author(s):  
Shusuke Ukita ◽  
Hiroshi Ohtani ◽  
Mitsuhiro Hasebe
Keyword(s):  
Ternary Compound ◽  
Thermodynamic Analysis ◽  
Binary Systems ◽  
Ternary Phase Diagram ◽  
Thermodynamic Description ◽  
Experimental Information ◽  
Full Potential ◽  
Calphad Approach ◽  
Plane Wave Method ◽  
Linearized Augmented Plane Wave

A thermodynamic analysis of the Ti-Zr-H ternary system has been performed by combining first-principles calculations with the CALPHAD approach. To enable the thermodynamic description of the binary systems, the results from our previous evaluation were adopted for the Ti-H, Zr-H, and Ti-Zr systems. The ternary compound, Ti2ZrH4, with an Fd3m-type crystal structure, exists over a wide composition range, and the (Ti)2(Zr)1(H,Va)4-type three-sublattice model was applied to describe its thermodynamic properties. Because of the lack of experimental information available, the enthalpy of formation of the Ti2ZrH4 phase was evaluated using the Full Potential Linearized Augmented Plane Wave method, and the estimated values were introduced into a CALPHAD-type thermodynamic analysis with some other experimental information. The calculated phase diagrams and the hydrogen isotherms were in good accordance with previous experimental results. Our calculations revealed that the ternary compound decomposes into a bcc and gas phase in the vicinity of 1270 K.

Thermodynamic Analysis of Steels by Incorporating First-Principles Calculations into the CALPHAD Approach

2007 ◽  
Vol 539-543 ◽  
pp. 2413-2418 ◽  
Author(s):  
Hiroshi Ohtani ◽  
N. Hanaya ◽  
Mitsuhiro Hasebe
Keyword(s):  
Phase Diagrams ◽  
Thermodynamic Analysis ◽  
First Principles ◽  
Experimental Information ◽  
Full Potential ◽  
Calphad Approach ◽  
First Principles Calculations ◽  
Plane Wave Method ◽  
Ternary Phase Diagrams ◽  
High Degree

A thermodynamic analysis of the Fe−M−P (M = Nb, Ti) ternary system has been performed by combining first-principles calculations with the CALPHAD approach. Because of the lack of experimental information available, thermodynamic properties of orthorhombic anti-PbCl2-type FeMP were evaluated using the Full Potential Linearized Augmented Plane Wave method, and the estimated values were introduced into a CALPHAD-type thermodynamic analysis. Applying this procedure, the phase diagrams of the Fe−M−P ternary phase diagrams whose contents are uncertain so far were calculated with a high degree of probability. Phase diagrams for high-purity ferritic stainless steels obtained following the same procedure are also presented.

First-Principles Studies of the Magnetic Properties of hcp Cr in Cr/Cu(111) and Cr/Ru(0001) Superlattices

2002 ◽  
Vol 721 ◽  
Author(s):  
G. Y. Guo
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Recent Observation ◽  
Theoretical Calculations ◽  
Ferromagnetic State ◽  
Full Potential ◽  
Generalized Gradient ◽  
Plane Wave Method ◽  
Wide Range ◽  
Linearized Augmented Plane Wave

AbstractLatest first-principles density functional theoretical calculations using the generalized gradient approximation and highly accurate all-eleectron full-potential linearized augmented plane wave method, show that bulk hcp Cr would be a paramagnet and that no ferromagnetic state could be stabilized over a wide range of volume [1]. To understand the recent observation of the weakly ferromagnetic state of Cr in hcp Cr/Ru (0001) superlattices [2], the same theoretical calculations have been carried out for the hcp Cr3/Ru7 (0001) and hcp Cr3/fcc Cu6 (111) superlattices. The Cr/Ru superlattice is found to be ferromagnetic with a small magnetic moment of ∼0.31μB/Cr while in contrast, Cr/Cu superlattice is found to be nonmagnetic.

FIRST-PRINCIPLE THEORETICAL STUDY ON THE CALCIUM FERRITE-TYPE LiMn2O4

2010 ◽  
Vol 03 (02) ◽  
pp. 93-96 ◽  
Author(s):  
MEILING LI ◽  
YUE ZHANG ◽  
LIN LI
Keyword(s):  
Magnetic Moments ◽  
Mixed Valence ◽  
Calcium Ferrite ◽  
Full Potential ◽  
Augmented Plane Wave ◽  
Plane Wave Method ◽  
Augmented Plane Wave Method ◽  
Structural And Electronic Properties ◽  
Mixed Valence Compound ◽  
Linearized Augmented Plane Wave

The structural and electronic properties of the calcium ferrite-type LiMn 2 O 4 were studied using the full-potential linearized augmented plane wave method. The results showed that LiMn 2 O 4 was an antiferromagnetic semiconductor from GGA+U calculations, similar to the experimental report of Li 0.92 Mn 2 O 4. The spin magnetic moments and density of states of Mn atoms showed that LiMn 2 O 4 was a mixed-valence compound with Mn 3+ and Mn 4+ cations randomly distributed amongst the octahedral sites.

Ferromagnetic Material of the Nearly Half-Metallic Alloy Co2TiGa

2013 ◽  
Vol 690-693 ◽  
pp. 590-593 ◽  
Author(s):  
Hong Pei Han
Keyword(s):  
Spin Polarization ◽  
Heusler Alloy ◽  
Ferromagnetic Material ◽  
Full Potential ◽  
Half Metallic ◽  
Augmented Plane Wave ◽  
Plane Wave Method ◽  
Linearized Augmented Plane Wave ◽  
Full Heusler ◽  
Metallic Ferromagnetism

The structure, electronic and magnetic properties of full-Heusler alloy Co2TiGa are investigated by means of the full potential linearized augmented plane-wave method. Our results show that the ground state of Co2TiGa is of the nearly half-metallic ferromagnetism with a magnetic moment of 1.00218μBper unit cell, which are contributed by the atoms Co and Ti. Meanwhile, the spin polarization around the Fermi level is up to 93.2%, almost 100%, which indicates that full-Heusler alloy Co2TiGa with the well magnetism and spin polarization would be possibly applied to the field of the material engineering and information technology.

Research on Topological Insulating Materials Induced by Uniaxial Strains with Properties of Insulating Materials

2013 ◽  
Vol 675 ◽  
pp. 180-183
Author(s):  
Hong Pei Han ◽  
Xin Ping Dong
Keyword(s):  
Electronic Band Structure ◽  
Full Potential ◽  
Electronic Band ◽  
Insulating Materials ◽  
Augmented Plane Wave ◽  
Plane Wave Method ◽  
Low Energy Consumption ◽  
Temperature Application ◽  
Insulating Phase ◽  
Linearized Augmented Plane Wave

A series of calculations are carried out to investigate systematically the electronic band structure of bulk HgTe under uniaxial strains with the relaxed-volume by means of the full potential linearized augmented plane-wave method. Our results show that there is a topological insulating phase induced by proper uniaxial strains, which is consistent with previous theoretical and experimental results. Interestingly, the strain-induced band gap is large up to 0.21 and 0.17 eV in expansion and compression along c-direction, respectively. It is indicated that the bulk HgTe under proper uniaxial strains would be possibly made the room temperature application for material engineering with low energy consumption.

Ab initio studies of the structural, electronic, and optical properties of quaternary BxAlyGa1–x–yN compounds

2016 ◽  
Vol 71 (2) ◽  
pp. 125-134 ◽  
Author(s):  
M’hamed Larbi ◽  
Rabah Riane ◽  
Samir F. Matar ◽  
Ahmed Abdiche ◽  
Mustapha Djermouni ◽  
...  
Keyword(s):  
Bulk Modulus ◽  
Local Density ◽  
Lattice Parameter ◽  
Band Gaps ◽  
Full Potential ◽  
Generalized Gradient ◽  
Augmented Plane Wave ◽  
Plane Wave Method ◽  
Structural And Electronic Properties ◽  
Linearized Augmented Plane Wave

AbstractOriginal first-principles calculations were performed to study the structural and electronic properties of quaternary BxAlyGa1–x–yN compounds, using the non-relativistic full-potential linearized augmented plane wave method as employed in the Wien2k code. For the exchange-correlation potential, local density approximation and generalized gradient approximation have been used to calculate theoretical lattice parameters, bulk modulus, and their pressure derivatives. Non-linear variation with compositions x and y of the lattice parameter, bulk modulus, and direct and indirect band gaps have been found. The calculated bowing of the fundamental band gaps is in good agreement with the available experimental and theoretical values.

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