scholarly journals Phase Stability and Site Preference of Tb-Fe-Co-V Compounds

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Jing Sun ◽  
Jiang Shen ◽  
Ping Qian
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Phase Stability ◽  
Random Motion ◽  
Inversion Method ◽  
Site Preference ◽  
Lattice Constants ◽  
Pair Potentials ◽  
Wide Range ◽  
Experimental Values

The effect of cobalt on the structural properties of intermetallicTb3Fe27.4−xCoxV1.6with Nd3(Fe,Ti)29structure has been studied by using interatomic pair potentials obtained through the lattice inversion method. Calculated results show that the preferential occupation site of the V atom is found to be the 4i(Fe3) site, and Fe atoms are substituted for Co atoms with a strong preference for the 8j(Fe8) site. The calculated lattice constants coincide quite well with experimental values. The calculated crystal structure can recover after either an overall wide-range macrodeformation or atomic random motion, demonstrating that this system has the stable structure of Nd3(Fe,Ti)29. All these prove the effectiveness of interatomic pair potentials obtained through the lattice inversion method in the description of rare-earth materials.

Atomistic Simulation for the Site Preference of Tb3(Fe28-XCoX)V1.0 Compounds

2012 ◽  
Vol 535-537 ◽  
pp. 1015-1018
Author(s):  
Jing Sun ◽  
Shuo Huang ◽  
Jiang Shen ◽  
Ping Qian
Keyword(s):  
Rare Earth ◽  
Structural Properties ◽  
Atomistic Simulation ◽  
Experimental Results ◽  
Inversion Method ◽  
Site Preference ◽  
Lattice Constants ◽  
Pair Potentials ◽  
Experimental Values ◽  
Good Agreement

The effect of cobalt on the structural properties of intermetallic Tb3(Fe28-xCox)V1.0with Nd3(Fe,Ti)29structure has been studied by using interatomic pair potentials obtained through the lattice inversion method. Calculated results show that the order of site preference of cobalt is 8j(Fe8), 4e(Fe11) and 2c(Fe1) which is in good agreement with experimental results. And the calculated lattice constants coincide quite well with experimental values. All these prove the effectiveness of interatomic pair potentials obtained through the lattice inversion method in the description of rare-earth materials.

Atomistic Simulation of Site Preference and Lattice Vibrations in UtXAl12-X ( T = Zr, Nb, Mo and Fe ) and their Related Hydrides

2011 ◽  
Vol 261-263 ◽  
pp. 730-734
Author(s):  
Li Jun Bai ◽  
Ping Qian ◽  
Yao Wen Hu ◽  
Jiu Li Liu
Keyword(s):  
Thermodynamic Properties ◽  
Calculated Result ◽  
Atomistic Simulation ◽  
Lattice Parameters ◽  
Inversion Method ◽  
Site Preference ◽  
Lattice Vibrations ◽  
Pair Potentials ◽  
Densities Of States ◽  
Experimental Values

The site preference and thermodynamic properties of UTxAl12-x(T = Zr, Nb, Mo and Fe) and their related hydrides are studied based on the pair potentials obtained by the lattice inversion method. The calculated result demonstrates that the stabilizing elements Zr, Nb, or Mo prefer to substitute for Al in 8isites; and Fe atom preferentially substitutes for Al in the 8fsite. The interstitial H atoms only occupy 2binterstitial sites in UTxAl12-x. The calculated lattice parameters coincide with the experimental values. In addition, the total and partial phonon densities of states are first evaluated for these compounds.

Structural Simulation and Lattice Vibration of a3Ni5Al19 (A = Th, U)

2011 ◽  
Vol 233-235 ◽  
pp. 2310-2314
Author(s):  
Jiu Li Liu ◽  
Ping Qian ◽  
Yao Wen Hu ◽  
Li Jun Bai ◽  
Jiang Shen
Keyword(s):  
Transition Metals ◽  
Intermetallic Compounds ◽  
Phase Stability ◽  
Atomistic Simulation ◽  
Lattice Vibration ◽  
Inversion Method ◽  
Vibrational Modes ◽  
Lattice Constants ◽  
Pair Potentials ◽  
Densities Of States

An atomistic simulation is presented on the phase stability and lattice parameters of the new actinide intermetallic compounds A3Ni5Al19(A = Th, U). Calculations are based on a series of interatomic pair potentials related to the actinides and transition metals, which are obtained by lattice inversion method. Calculated lattice constants are found to agree with a report in the literature. It is noted that, the total and partial phonon densities of states are first evaluated for the A3Ni5Al19(A = Th, U) compounds. The analysis for the inverted potentials explains qualitatively the contributions of different atoms to the vibrational modes.

Atomistic Simulation on the Structure and Lattice Vibrations of Fe7-xCrxC3 Carbides

2012 ◽  
Vol 591-593 ◽  
pp. 912-916
Author(s):  
Zhen Feng Zhang ◽  
Ping Qian ◽  
Jin Chun Li ◽  
Jiang Shen
Keyword(s):  
Transition Metal ◽  
Hexagonal Structure ◽  
Inversion Method ◽  
Site Preference ◽  
Metal Carbides ◽  
Lattice Constants ◽  
Transition Metal Carbides ◽  
Pair Potentials ◽  
Densities Of States ◽  
Good Agreement

The phase stability and site preference of transition metal carbides Cr in Fe7-xCrxC3 are studied based on the pair potentials obtained by the lattice inversion method. The lattice constants and cohesive energy of Fe7-xCrxC3 with the content x are calculated. The results show that Cr atoms substitute for Fe with a strong preference for the 6c1 sites and the order of site preference is 6c1, 6c2 and 2b. Calculated lattice parameters are in good agreement with the experimental data. Moreover, the total and partial phonon densities of states are first evaluated for the Fe7-xCrxC3 compounds with the hexagonal structure. We also provide some information on the vibrational properties of transition metal carbides, such as the specific heat and Debye temperature were also evaluated.

scholarly journals Towards an accurate description of perovskite ferroelectrics: exchange and correlation effects

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Simuck F. Yuk ◽  
Krishna Chaitanya Pitike ◽  
Serge M. Nakhmanson ◽  
Markus Eisenbach ◽  
Ying Wai Li ◽  
...  
Keyword(s):  
Density Functional ◽  
General Purpose ◽  
Correlation Effects ◽  
Lattice Constants ◽  
Bulk Solids ◽  
Wide Range ◽  
Exchange Enhancement ◽  
Experimental Values ◽  
Similar Accuracy ◽  
Ferroelectric Oxides

Abstract Using the van der Waals density functional with C09 exchange (vdW-DF-C09), which has been applied to describing a wide range of dispersion-bound systems, we explore the physical properties of prototypical ABO 3 bulk ferroelectric oxides. Surprisingly, vdW-DF-C09 provides a superior description of experimental values for lattice constants, polarization and bulk moduli, exhibiting similar accuracy to the modified Perdew-Burke-Erzenhoff functional which was designed specifically for bulk solids (PBEsol). The relative performance of vdW-DF-C09 is strongly linked to the form of the exchange enhancement factor which, like PBEsol, tends to behave like the gradient expansion approximation for small reduced gradients. These results suggest the general-purpose nature of the class of vdW-DF functionals, with particular consequences for predicting material functionality across dense and sparse matter regimes.

Atomistic Study on the Structural Stability and Site Preference of Rh7-xTxB3 (T = Fe, Cr and Mn)

2013 ◽  
Vol 739 ◽  
pp. 47-50
Author(s):  
Xiao Xu Wang ◽  
Ping Qian ◽  
Zhi Wei An ◽  
Zhen Feng Zhang ◽  
Jiang Shen ◽  
...  
Keyword(s):  
Structural Properties ◽  
Atomistic Simulation ◽  
Complex Structure ◽  
Inversion Method ◽  
Site Preference ◽  
Cell Parameters ◽  
Pair Potentials ◽  
Temperature Disturbance ◽  
Global Deformation ◽  
Atomistic Study

An atomistic simulation of the structural properties of the Rh7-xTxB3 series, where T is Fe, Cr, Mn, has been carried out using interatomic pair potentials based on the lattice inversion method. Calculated results show T atoms can stabilize Rh7-xTxB3 with Th7Fe3-type structure, and T atoms substitute for Rh with a strong preference for the 2b sites. The phase stability of the intermetallics Rh7-xTxB3 is tested by many means including random atom shift, global deformation and high temperature disturbance under the control of the pair potentials. Calculated unit-cell parameters for Rh7-xTxB3 agree with the experimental data very well. All the above results indicate that the potentials are valid for studying the structural properties of these kinds of complex structure of transition metal boride.

THEORETICAL INVESTIGATION ON THE PHASE STABILITY AND SITE PREFERENCE OF R(Co,T)12 AND R(Co,T)12Nx (R = Y, Ce, Pr, Nd, Sm, Gd, Tb, Ho, Er, Dy, T = Mo, Mn, Ni)

2003 ◽  
Vol 17 (08) ◽  
pp. 329-338 ◽  
Author(s):  
JIANG SHEN ◽  
PING QIAN ◽  
NAN-XIAN CHEN
Keyword(s):  
Nitrogen Atom ◽  
Ab Initio ◽  
Phase Stability ◽  
Site Preference ◽  
Interatomic Potentials ◽  
X Ray ◽  
Pair Potentials ◽  
Rare Earth Intermetallic Compounds ◽  
Ray Patterns ◽  
Good Agreement

The phase stability and site preference of some ternary elements of ThMn12 type rare-earth intermetallic compounds R ( Co , T )12 and R ( Co , T )12 N x are evaluated based on ab initio converted interatomic potentials. The calculated results show that adding either Mo or Mn makes the crystal cohesive energy decrease markedly. It proved that these elements can stabilize R ( Co , T )12 with the ThMn12 structure. The systemic energy is the lowest when T atoms occupy symmetrically 8i sites. For T = Mo or Mn, the doped nitrogen atom does not affect the order of site preference of these stabilizing elements. Moreover, the nitrogen atom occupies 2b sites. According to the calculated results, it can be seen that lattice parameters and X-ray patterns are in good agreement with experiment. All the above results indicate that the ab initio converted pair potentials are effective for the calculation of these kinds of anisotropy materials and some related nitrides.

Theoretical Investigation on the Phase Stability and Site Preference of R(Co,T)12 and R(Co,T)12Nx(R=Y, Ce, Pr, Nd, Sm, Gd, Tb, Ho, Er, Dy, T=Mo, Mn, Ni)

2003 ◽  
Vol 17 (17) ◽  
pp. 897-907 ◽  
Author(s):  
Jiang Shen ◽  
Ping Qian ◽  
Nan-Xian Chen
Keyword(s):  
Nitrogen Atom ◽  
Ab Initio ◽  
Phase Stability ◽  
Site Preference ◽  
Interatomic Potentials ◽  
X Rays ◽  
Pair Potentials ◽  
Rare Earth Intermetallic Compounds ◽  
Good Agreement ◽  
Rare Earth Intermetallic

The phase stability and site preference of some ternary elements of ThMn 12 type rare-earth intermetallic compounds R(Co,T) 12 and R(Co,T) 12 N x are evaluated based on ab initio converted interatomic potentials. The calculated results show that adding either Mo or Mn makes the crystal cohesive energy decrease markedly. It proved that these elements can stabilize R(Co,T) 12 with ThMn 12 structure. The systemic energy is the lowest when T atoms occupy symmetrically 8i sites. For T=Mo or Mn, the doped nitrogen atom does not affect the order of site preference of these stabilizing elements. Moreover, the nitrogen atom occupies 2b sites. According to the calculated results, it can be seen that lattice parameters and X-rays are in good agreement with experiment. All the above results indicate that the ab initio converted pair potentials are effective for the calculation of these kinds of anisotropy materials and some related nitrides.

THEORETICAL STUDY OF PHASE FORMING, MAGNETIZATION AND LATTICE VIBRATIONS OF Fe23-xTxB6(T = Cr, Mn, Ni, C), Fe23 C6, Fe23B6 AND Fe23CB6

2013 ◽  
Vol 27 (12) ◽  
pp. 1350050 ◽  
Author(s):  
XIAO-XU WANG ◽  
PING QIAN ◽  
ZHI-WEI AN ◽  
YA-PING LI ◽  
ZHEN-FENG ZHANG ◽  
...  
Keyword(s):  
Theoretical Investigation ◽  
Phase Stability ◽  
Theoretical Study ◽  
Magnetic Moments ◽  
Site Preference ◽  
Vibrational Modes ◽  
Lattice Vibrations ◽  
Lattice Constants ◽  
Densities Of States ◽  
Prototype Structure

We present a theoretical investigation on the phase stability, site preference and lattice constants of Fe 23-x T x B 6( T = Cr , Mn , Ni , C ), Fe 23 C 6 and Fe 23 CB 6. The calculated results show that in Fe 23-x T x B 6 the Cr , Mn or Ni atoms prefer 4a sites. Fe 23 CB 6 may form with Cr 23 C 6 prototype structure, and the carbon atoms are positioned at 4a sites. The calculated lattice constants are found to agree with report in literatures. We have calculated the magnetic moments of Fe 23 C 6, Fe 23 B 6 and Fe 23 CB 6 compounds. Furthermore, the total and partial phonon densities of states are evaluated first for these compounds. The analysis of the inverted potentials explains qualitatively the contributions of different atoms to the vibrational modes.

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