NRI Institute of Research and Technology

Bhopal, India

NRI Institute of Research and Technology

Bhopal, India
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Dar S.A.,Government Motilal Vigyan Mahavidyalya College | Srivastava V.,NRI Institute of Research and Technology | Sakalle U.K.,SNPG College
Journal of Superconductivity and Novel Magnetism | Year: 2017

For the first time, the americium-based perovskite SrAmO3 has been studied with respect to its structural, electronic, magnetic, mechanical, and thermodynamic properties. The study has been carried within the well-known density functional theory (DFT) using different approximations such as local spin density approximation (LSDA), generalized gradient approximation (GGA), LSDA + U, GGA + U. In order to check for the stable ground state, optimization was performed for non-magnetic, ferromagnetic, and anti-ferromagnetic phases, and the compound was found to be stable in the ferromagnetic phase. The spin magnetic moment was obtained with different exchange correlations and was found to be an integer which is one of the consequences of half-metallic nature. The half-metallic nature of SrAmO3 was also confirmed from spin-polarised band structure calculations using GGA, GGA + U, and mBJ, showing metallic nature in spin-up states and semi-conducting in spin-down states. The elastic constants, Young modulus, shear modulus, Poisson ratio, and anisotropic factor were also calculated. SrAmO3 was found to establish ductile and anisotropic nature. Debye temperature was predicted to be 353 K from elastic constants. The thermodynamic properties, like variation of specific heat capacity, thermal expansion, and entropy, were studied in the temperature range of 0 to 600 K. © 2017 Springer Science+Business Media New York


Dar S.A.,Government Motilal Vigyan Mahavidyalya College | Srivastava V.,NRI Institute of Research and Technology | Sakalle U.K.,P.A. College | Ahmad Khandy S.,Jiwaji University | Gupta D.C.,Jiwaji University
Journal of Superconductivity and Novel Magnetism | Year: 2017

The structural, electronic, mechanical and thermodynamic properties of the perovskite oxide BaAmO3 have been predicted using the full-potential linearized augmented plane wave (FP-LAPW) method. The equilibrium lattice constant, bulk modulus and pressure derivative were computed using different exchange correlations. The optimization of structure was carried out in ferromagnetic, anti-ferromagnetic and non-magnetic states, and the compound was found to be stable in the ferromagnetic state. A systematic study on the band structure and density of states was accomplished using generalized gradient approximation (GGA), Hubbard approximation (GGA + U) and modified Becke–Johnson exchange potential (mBJ),and the compound was found to have a half-metallic nature in all the approximations. The calculated total spin magnetic moment was found to be 5 μB in all the approximations used. The second-order elastic constants, Young modulus, shear modulus, Poisson ratio and anisotropic factor have also been calculated. In order to have a complete understanding of BaAmO3, the thermodynamic properties were studied in the pressure range of 0 to 40 GPa and the temperature range extending from 0 to 600 K. © 2017 Springer Science+Business Media New York


Paliwal N.,University Bhopal | Srivastava V.,NRI Institute of Research and Technology
AIP Conference Proceedings | Year: 2016

The tight binding linear muffin-Tin-orbital (TB-LMTO) method within the local density approximation (LDA has been used to calculate structural and electronic properties of thallium pnictides TlX (X=Sb, Bi) at high pressure. As a function of volume, the total energy is evaluated. Apart from this, the lattice parameter (a0), bulk modulus (B0), band structure (BS) and density of states (DOS) are calculated. From energy band diagram we observed metallic behaviour in TlSb and TlBi compounds. The values of equilibrium lattice constants and bulk modulus are agreed well with the available data. © 2016 Author(s).


Dar S.A.,Government Motilal Vigyan Mahavidyalya College | Srivastava V.,NRI Institute of Research and Technology | Sakalle U.K.,P.A. College
Journal of Electronic Materials | Year: 2017

A combined high pressure and temperature investigation on recently reported cubic perovskite PbMoO3 have been performed within the most accurate density functional theory (DFT). The structure was found stable in cubic paramagnetic phase. The DFT calculated analytical and experimental lattice constant were found in good agreement. The analytical tolerance factor as well as the elastic properties further verifies the cubic stability for PbMoO3. The spin polarized electronic band structure and density of states presented metallic nature with symmetry in up and down states. The insignificant magnetic moment also confirms the paramagnetic nature for the compound. The high pressure elastic and mechanical study up to 35 GPa reveal the structural stability of the material in this pressure range. The compound was found to establish a ductile nature. The electrical conductivity obtained from the band structure results show a decreasing trend with increasing temperature. The temperature dependence of thermodynamic parameters such as specific heat (Cv), thermal expansion (α) has also been evaluated. © 2017 The Minerals, Metals & Materials Society


Singh A.,Sadhu Vaswani College | Singh A.,Barkatullah University | Srivastava V.,Barkatullah University | Srivastava V.,NRI Institute of Research and Technology | And 2 more authors.
Journal of Nuclear Materials | Year: 2010

We report an ab initio calculation of pressure-induced structural phase transition and electronic properties of the NaCl-type Cm-based pnictides namely CmX (X = N, P, As, Sb and Bi). The total energy as a function of volume is obtained by means of self-consistent tight-binding linear muffin tin orbital (TB-LMTO) method by performing spin and non-spin polarized calculation. Magnetically the CmX compounds are stable in ferromagnetic (FM) state and their crystal structure is NaCl-type at ambient condition. From the present study, we predict a structural phase transition from ferromagnetic (FM) NaCl-type (B 1 phase) structure to ferromagnetic CsCl-type (B 2 phase) structure for curium pnictides in the pressure range of 51.0-10.0 GPa (CmN to CmBi). The pressure-induced transition is found to be first order. The band structure and density of states (DOS) are plotted in FM-B 1 phase and FM-B2 phase. Apart from this the groundstate properties like magnetic moment, lattice parameter and bulk modulus are calculated and compared with the available theoretical and experimental results. © 2010 Elsevier B.V. All rights reserved.


Pagare G.,P.A. College | Sen D.,Government Girls College | Srivastava V.,Barkatullah University | Srivastava V.,NRI Institute of Research and Technology | Sanyal S.P.,Barkatullah University
Journal of Physics: Conference Series | Year: 2010

We have investigated theoretically the high-pressure structural phase transition and cohesive properties of two heavy rare earth mono antimonides (RESb; RE Dy and Lu) by using two body interionic potential with necessary modifications to include the effect of Coulomb screening by the delocalized 4f electrons of the RE ion. The peculiar properties of these compounds have been interpreted in terms of the hybridization of f electrons with the conduction band and strong mixing of f states of RE ion with the p orbital of neighboring pnictogen ion. These compounds exhibit first order crystallographic phase transition from their NaCl (B 1) phase to CsCl (B 2) phase at 23.6 GPa and 25.4 GPa respectively. The bulk modulii of RESb compounds are obtained from the P-V curve fitted by the Birch equation of state. We also calculated the RE-RE distance as a function of pressure. Elastic properties of these compounds have also been studied and their second order elastic constants are calculated. © 2010 IOP Publishing Ltd.


Pagare G.,P.A. College | Srivastava V.,NRI Institute of Research and Technology | Sanyal S.P.,Barkatullah University | Rajagopalan M.,Anna University
Physica B: Condensed Matter | Year: 2011

The ground state electronic structure and thermal properties of B 2-type intermetallic compounds AlRE (RE: Pm, Sm, Eu, Tb, Gd and Dy) have been studied using a self-consistent tight-binding linear muffin-tin orbital (TB-LMTO) method at ambient as well as at high pressure. These compounds show metallic behavior under ambient condition. The band structure, total energy, density of states and ground state properties like lattice parameter, bulk modulus are calculated in the present work. The DebyeGrneisen model is used to calculate the Debye temperature and the Grneisen constant. The calculated results are in good agreement with the reported experimental and other theoretical results. The variation in the Debye temperature with pressure has also been reported. We present a detailed analysis of the role of f electrons of RE in the AlRE system. © 2010 Elsevier B.V. All rights reserved.


Srivastava V.,NRI Institute of Research and Technology | Srivastava V.,Barkatullah University | Bhajanker S.,NRI Institute of Research and Technology | Bhajanker S.,Barkatullah University | Sanyal S.P.,NRI Institute of Research and Technology
Physica B: Condensed Matter | Year: 2011

The structural and mechanical properties of LnO (Ln=Sm, Eu, Yb) compounds have been investigated using a modified interionic potential theory, which includes the effect of Coulomb screening. We predicted a structural phase transition from NaCl (B 1)- to CsCl (B 2)-type structure and elastic properties in LnO compounds at very high pressure. The anomalous properties of these compounds have been correlated in terms of the hybridisation of f-electrons of the rare earth ion with conduction band and strong mixing of f-states of lanthanides with the p-orbital of neighbouring chalcogen ion. For EuO, the calculated transition pressure, bulk modulus and lattice parameter are close to the experimental data. The nature of bonds between the ions is predicted by simulating the ionion (LnLn and LnO) distances at high pressure. The second order elastic constants along with shear modulus and Youngs modulus, elastic anisotropy and Poissons ratio are also presented for these oxides. © 2011 Elsevier B.V. All rights reserved.


Bhajanker S.,NRI Institute of Research and Technology | Bhajanker S.,Barkatullah University | Srivastava V.,NRI Institute of Research and Technology | Srivastava V.,Barkatullah University | Sanyal S.P.,Barkatullah University
Physica B: Condensed Matter | Year: 2012

The high pressure structural, elastic and thermal properties of holmium pnictides HoX (X=N, P, As and Bi) were investigated theoretically by using an inter-ionic potential theory with modified ionic charge parameter. We have predicted a structural phase transition from NaCl (B 1) to CsCl (B 2)-type structure at pressure of 139 GPa for HoN, 52 GPa for HoP, 44 GPa for HoAs and 26 GPa for HoBi. Other properties, such as lattice constant, bulk modulus, cohesive energy, second and third-order elastic constants were calculated and compared with the available experimental and theoretical data. In order to gain further information the brittle behaviour of these compounds was observed. Some other properties like Shear modulus (G), Youngs modulus (E), Poissons ratio (ν), anisotropy factor (A), sound velocities, Debye temperature (θ D) were calculated. The variation of elastic constants (C 11 and C 44) and Debye temperature (θ D) with pressure was also presented. © 2012 Elsevier B.V. All rights reserved.


Lohi S.A.,NRI Institute of Research and Technology | Motwani A.,NRI Institute of Research and Technology
Proceedings - 2014 4th International Conference on Communication Systems and Network Technologies, CSNT 2014 | Year: 2014

Information in the form of textual documents would have a huge growth due to the factors like digitization of libraries, exponential rise in internet usage, use of e-mail for various reasons, acceptability of soft copies for many works even critical financial work and other things. In view of these reasons, this paper discusses a new approach for Documentation Taxonomy (DT) based on combining efficient algorithms to be used for english language. The important aspect of automatically classifying and providing taxonomy to a set of documents into any taxonomical structure with the help of predefined categories is termed as Documentation Taxonomy. Automated Documentation Taxonomy is gaining prominence since it frees organizations from the frantic and time consuming need of manually organizing documents. This manual process can be expensive and given the time constraints of the application or the number of documents involved, simply not feasible. In terms of accuracy, modern documentation taxonomy systems proves better than that of trained human professionals, which is made possible by a combination of information retrieval technology and machine learning technology. This research put forwards a mechanism that shows that the use of combination of different algorithms brings down the ambiguity in taxonomical issues. There are numerable useful applications of this approach spanning various scientific and general fields of work. © 2014 IEEE.

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