Structural Analysis of Rare Earth Compound with NaCl-Structure

2016 ◽  
Vol 28 ◽  
pp. 53-58
Author(s):  
Purvee Bhardwaj ◽  
Sadhna Singh
Keyword(s):  
Rare Earth ◽  
Structural Properties ◽  
Structural Parameters ◽  
Structural Phase ◽  
Rare Earth Compound ◽  
Phase Transition Pressure ◽  
Volume Collapse ◽  
Cscl Type ◽  
Realistic Interaction ◽  
Good Agreement

The structural properties of rare earth compound in NaCl-structure are studied in the present investigation. To study these properties of erbium telluride (ErTe), the Realistic Interaction Potential Approach (RIPA) model has been used. Present compound shows NaCl-type to CsCl-type structural phase transformation. The structural properties, including phase transition pressure and volume collapse are obtained and compared with available literature. The calculated equilibrium structural parameters are in good agreement with the available experimental and theoretical results. Further more to study the electronic properties, band structure and density of state are reported.

First-Principle Study on the Structural Phase Transition, and Electronic Structures of Cobalt under Pressure

2015 ◽  
Vol 729 ◽  
pp. 15-20
Author(s):  
Hong Bo Zhu ◽  
Dun Qiang Tan ◽  
Zhi Huang Xiong
Keyword(s):  
Phase Transition ◽  
Electronic Structures ◽  
Density Functional ◽  
Structural Parameters ◽  
Structural Phase ◽  
First Principles Calculation ◽  
Functional Theory ◽  
Calculated Equilibrium ◽  
Theoretical Results ◽  
Good Agreement

The structural phase transitions and electronic structures of Co are investigated by using the first-principles calculation based on density-functional theory (DFT). Our calculated equilibrium structural parameters of Co are in good agreement with the available experimental data and other theoretical results. The calculated phase transition hcp-Co → fcc-Co at ca. 125.25 GPa. The magnetic moment of hcp-Co and fcc-Co drops to zero at 155 GPa and 77 GPa, respectively.

High Pressure Structural and Mechanical Properties of YBi and ScBi Compounds

2016 ◽  
Vol 1141 ◽  
pp. 39-43 ◽  
Author(s):  
Ashok K. Ahirwar ◽  
Mahendra Aynyas ◽  
Yeshvir Singh Panwar ◽  
Sankar P. Sanyal
Keyword(s):  
Phase Transition ◽  
Theoretical Study ◽  
Structural Phase ◽  
Theoretical Data ◽  
Second Order ◽  
Mechanical And Thermal Properties ◽  
First Order ◽  
Debye Temperatures ◽  
Phase Transition Pressure ◽  
Good Agreement

A theoretical study of first order pressure induced structural phase transition, mechanical and thermal properties of YBi and ScBi compounds have been investigated using the modified inter-ionic potential theory (MIPT), which parametrically includes the effect of coulomb screening. The calculated results of phase transition pressure of ScBi and YBi are agree well with the available theoretical data. We have also reported the second order elastic constants and Debye temperature of these compounds. Our calculated values of second order elastic constant C11, C12 and C44 are 128.4, 29.5, 30.2 GPa and 123.1, 29.7, 30.3 GPa for ScBi and YBi compounds respectively. These results are in good agreement with available theoretical data. We have also estimated Debye temperatures (θD) are 80K, 86K, for ScBi and YBi compounds respectively.

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.

Magnetic and structural phase transition in heavy rare-earth compound DyB6

1997 ◽  
Vol 241-243 ◽  
pp. 696-698 ◽  
Author(s):  
K Takahashi ◽  
H Nojiri ◽  
K Ohoyama ◽  
M Ohashi ◽  
Y Yamaguchi ◽  
...  
Keyword(s):  
Phase Transition ◽  
Rare Earth ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Heavy Rare Earth ◽  
Rare Earth Compound

Structural and elastic properties of barium chalcogenides (BaX, X=O, Se, Te) under high pressure

Open Physics ◽  
2008 ◽  
Vol 6 (2) ◽  
Author(s):  
Purvee Bhardwaj ◽  
Sadhna Singh ◽  
Neeraj Gaur
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Elastic Constants ◽  
Structural Phase ◽  
Transition Pressure ◽  
Phase Transition Pressure ◽  
Cscl Structure ◽  
Three Body ◽  
Derivatives Of ◽  
Good Agreement

AbstractIn the present paper we have investigated the high-pressure, structural phase transition of Barium chalcogenides (BaO, BaSe and BaTe) using a three-body interaction potential (MTBIP) approach, modified by incorporating covalency effects. Phase transition pressures are associated with a sudden collapse in volume. The phase transition pressures and associated volume collapses obtained from TBIP show a reasonably good agreement with experimental data. Here, the transition pressure, NaCl-CsCl structure increases with decreasing cation-to-anion radii ratio. In addition, the elastic constants and their combinations with pressure are also reported. It is found that TBP incorporating a covalency effect may predict the phase transition pressure, the elastic constants and the pressure derivatives of other chalcogenides as well.

High Pressure Structural Phase Transition and Elastic Properties of MgX (X = S, Se, Te) Semiconducting Compounds

2006 ◽  
Vol 987 ◽  
Author(s):  
Dinesh Varshney ◽  
Netram Kaurav ◽  
Kamal Kumar Choudhary ◽  
R. Kinge ◽  
R. K. Singh
Keyword(s):  
Phase Transition ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Repulsive Interaction ◽  
Interionic Interaction ◽  
Phase Transition Pressure ◽  
Cscl Type ◽  
Semiconducting Compounds ◽  
Structural Aspects ◽  
Vdw Interaction

AbstractPressure-induced structural aspects of NaCl-type (B1) to CsCl-type (B2) structure in MgX [X = S, Se, Te] semiconductors are presented. An effective interionic interaction potential (EIOP) with long range Coulomb, van der Waals (vdW) interaction and the short-range repulsive interaction upto second-neighbor ions within the Hafemeister and Flygare approach is developed. Particular attention is devoted to evaluate the vdW coefficients following the variational method, as both the cation and the anion are polarizable. Our result on vast volume discontinuity in pressure volume phase diagram identifies the structural phase transition from B1 to B2 structure. The estimated value of the phase transition pressure (Pt) is consistent with results previously published. The variations of elastic constants with pressure follow a systematic trend identical to that observed in others compounds of NaCl type structure family.

Structural Properties of CaS1-xSex Mixed Crystal under High Pressure

2014 ◽  
Vol 1047 ◽  
pp. 51-59
Author(s):  
Anita Singh ◽  
Ekta Sharma ◽  
Umesh Kumar Sakalle
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Structural Properties ◽  
Rock Salt ◽  
Cesium Chloride ◽  
Relative Volume ◽  
Transition Pressure ◽  
Phase Transition Pressure ◽  
Volume Collapse ◽  
Vegard’S Law

The mixed ionic crystals are formed by the mixing of pure components and are truly crystalline and their lattice constants change linearly with concentration from one pure member to another. The present work is intended to investigate structural properties of CaS1-xSexunder high pressure. The structural properties of mixed compound CaS1-xSex(0≤x≤1) under high pressures have been evaluated using three body potential model (TBPM). This interaction potential has been calculated by using three model parameters. For this mixed compound, the experimental data has been generated by the application of Vegard’s law to experimental values available for pure end-point members.The Structure of CaS and CaSe has been Rock Salt (B1) at ambient pressure and with increasing pressure Rock Salt (B1) structure undergo a transition in Cesium Chloride (B2) at 40GPa and 38 GPa respectively and CaS1-xSexunder goes Rock Salt to Cesium Chloride (B1→B2) structure. The difference in phase transition pressure in end-point members is low. In the present work we have investigated structural properties at high pressure for five different concentration x (x=0, 0.25, 0.50, 0.75, 1) for CaS1-xSex. Phase transition pressure and relative volume collapse at different phase transition pressure for different values of x has been calculated. Predicted phase transition pressure and relative volume collapse are found in good agreement with experimental and other theoretical data. Linear variation of phase transition pressure and lattice constant of different composition show that Vegard’s law is valid for this alloy. We have evaluated the phase transition pressure from graphical analysis where the Gibb’s free energy difference ΔG [G(B1)-G(B2)] have been plotted against pressure (P) for CaS1-xSexfor different concentration x. The pressure at which ΔG approaches zero corresponds to phase –transition pressure (Pt). The relative volume changes, ΔV(Pt)/V(0), associated with the above mentioned compression have also been computed and plotted against pressure to get the phase diagram for CaS1-xSexin different concentration.

scholarly journals PHASE TRANSITION OF PRASEODYMIUM MONO-PNICTIDES UNDER HIGH PRESSURE

2013 ◽  
Vol 22 ◽  
pp. 491-496
Author(s):  
DINESH CHANDRA GUPTA ◽  
GAJENDRA SINGH RAYPURIA
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Relative Volume ◽  
Many Body ◽  
Rare Earth Atom ◽  
Phase Transition Pressure ◽  
Volume Collapse ◽  
Cscl Type ◽  
Nearest Neighbours ◽  
Many Body Interactions

The Phase transition and elastic properties of Praseodymium-monopnictides have been investigated under pressure by means of a modified charge-transfer potential model which incorporates the Coulomb screening due to the delocalization of f-electron of rare-earth atom leading to many-body interactions, along with Coulomb interaction, covalency effect and overlap repulsion extended up to second-nearest neighbours. These compunds undergo transition from NaCl structure to high pressure body-centered tetragonal (BCT) structure (distorted CsCl-type P4/mmm). The calculated values of cohesive energy, lattice constant, phase transition pressure, relative volume collapse. Present model explains the Cauchy’s discrepancy correctly.

STRUCTURAL PHASE TRANSITION IN BORON COMPOUNDS AT HIGH PRESSURE

2010 ◽  
Vol 24 (10) ◽  
pp. 1235-1244 ◽  
Author(s):  
MINA TALATI ◽  
PRAFULLA K. JHA
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Elastic Constants ◽  
Structural Phase ◽  
Boron Compounds ◽  
Potential Approach ◽  
Transition Pressure ◽  
Zinc Blende ◽  
Phase Transition Pressure ◽  
Good Agreement

The high-pressure induced structural phase transitions and pressure induced elastic and anharmonic behavior of boron compounds viz. BN, BP, and BAs have been investigated using an inter-ionic potential approach based on charge transfer effect. These compounds go to NaCl phase (B1) under pressure from zinc blende phase (B3). The variations of second-order elastic constants and their combinations follow a systematic trend with pressure, identical to that observed in other compounds of zinc blende structure family. Shear stiffness constants decrease with increasing pressure up to phase transition pressure. The bulk moduli of these compounds are in reasonably good agreement with other theoretical and experimental data. The values of phase transition pressure of these compounds obtained by using the present approach are also in good agreement with those predicted by using the pseudo potential approach. The present approach has also succeeded in predicting the Born and relative stability criterion for stable zinc blende phase of these compounds. We also present a set of third-order elastic constants and pressure derivatives of second-order elastic constants for boron compounds.

Pressure Induced Structural Phase Transition in InP at Room Temperature

2016 ◽  
Vol 28 ◽  
pp. 98-100
Author(s):  
Pooja Pawar ◽  
Shilpa Kapoor ◽  
Sadhna Singh
Keyword(s):  
Phase Transition ◽  
Structural Phase ◽  
Theoretical Data ◽  
Effect Of Temperature ◽  
Repulsive Interaction ◽  
Transition Pressure ◽  
Phase Transition Pressure ◽  
Realistic Interaction ◽  
Range Overlap ◽  
Three Body

We have investigated the pressure induced phase transition of InP from ZB to NaCl structure associated by using realistic interaction potential model (RIPM), which is modified by taking effect of temperature. This model consists of coulomb interaction, three body interaction, and short range overlap repulsive interaction up to second nearest neighbour. Phase transition pressure is associated with a sudden collapse in volume showing the incidence of first order phase transition. The phase transition pressure and associated volume collapses obtained from present model show a generally good agreement with the available experimental and theoretical data.

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