Sri Sathya Sai College for Women

Bhopal, India

Sri Sathya Sai College for Women

Bhopal, India

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Srivastava A.,Sri Sathya Sai College for Women | Gaur N.K.,Barkatullah University
Key Engineering Materials | Year: 2013

With the objective of exploring the unknown thermodynamic phase diagram of Bi1- xSrxMnO3 family, we present here an investigation of the temperature-dependent (10K < T < 900K) thermodynamic behavior of Bi1-xSrxMnO3 (x=0.25, 0.30, 0.50). We report here probably for the first time the thermal expansion and specific heat along with other thermal properties of strontium doped perovskite manganite BiMnO3. The specific heat values revealed by using RIM are in closer agreement with the available experimental data for some concentrations (x) of Bi1-xSrxMnO3. In addition, the results on the cohesive energy (φ) in orthorhombic perovskite phase, molecular force constant (f), Reststrahlen frequency (vo) and Gruneisen parameter (γ) are also presented. Copyright © 2013 Trans Tech Publications Ltd.


Srivastava A.,Sri Sathya Sai College for Women | Thakur R.,Barkatullah University | Gaur N.K.,Barkatullah University
AIP Conference Proceedings | Year: 2014

Specific heat (Cp) thermal expansion (α) and Bulk modulus (BT) of lightly doped Rare Earth manganites (La0.3Pr0.7)0.65Ca0. 35Mn1-xBxO3 (B3+=Fe3+,Cr3+,Ga3+,Al3+,Ru4+); (0.3


Thakur R.,Barkatullah University | Thakur R.K.,Barkatullah University | Srivastava A.,Sri Sathya Sai College for Women | Gaur N.K.,Barkatullah University
AIP Conference Proceedings | Year: 2014

With the objective of exploring the unknown thermodynamic behavior of LaCo1-xNixO3 family, we present here an investigation of the temperature-dependent (10K ≤ T ≤ 300K) thermodynamic properties of LaCo1-xNixO3 (x=0.1, 0.3, 0.5). The specific heat of LaCoO3 with Ni doping in the perovskite structure at B-site has been studied by means of a Modified Rigid Ion Model (MRIM). This replacement introduces large cation variance at B-site hence the specific heat increases appreciably. We report here probably for the first time the cohesive energy, Reststrahlen frequency (υ) and Debye temperature (θD) of LaCo1-xNixO3 compounds. © 2014 AIP Publishing LLC.


Thakur R.,Barkatullah University | Srivastava A.,Sri Sathya Sai College for Women | Thakur R.K.,Barkatullah University | Gaur N.K.,Barkatullah University
Journal of Alloys and Compounds | Year: 2012

We have reported the temperature dependence (5 K ≤ T ≤ 1000 K) of the lattice contribution to the specific heat of rhombohedral LaCoO 3 and orthocobaltates RCoO 3 (R = Pr and Nd). The strong electron phonon interactions are present in these compounds and lattice distortions can affect them substantially. Thus Rigid Ion Model (RIM) is used for the first time to study the cohesive and thermal properties of the cobaltates RCoO 3 with rare earth cation (R = La, Pr and Nd). The values of specific heat calculated by us have shown remarkably good agreement with corresponding experimental data. In addition, the results on the temperature dependence of cohesive energy (φ), molecular force constant (f), Reststrahlen frequency (υ), Debye temperature (θ D) and Gruneisen parameter (γ) are also reported. © 2011 Elsevier B.V. All rights reserved.


Srivastava A.,Sri Sathya Sai College for Women | Gaur N.K.,Barkatullah University
AIP Conference Proceedings | Year: 2011

With the objective of exploring the unknown thermodynamic phase diagram of Pr1-xSrxMnO3 perovskite family around the half doping levels and above, we present here an investigation of the temperature-dependent (20 K


Srivastava A.,Barkatullah University | Srivastava A.,Sri Sathya Sai College for Women | Gaur N.K.,Barkatullah University
Journal of Physics: Conference Series | Year: 2010

The elastic and thermal properties of perovskite manganites La 1-xSrxMnO3 (x = 0.165, 0.185, 0.20, 0.40, 0.70, 0.80, 0.90, 1.0) have been studied as a function of temperature (1K≤T≤300K) by means of Atoms in Molecules (AIM) theory and a Modified Rigid Ion Model (MRIM) respectively. The specific heat values (Cv) and the Debye temperatures obtained by us from the lattice contributions are in reasonably good agreement with the available experimental data for some concentrations (x) of La1-xSrxMnO3. In addition, the results on the Bulk Modulus (BT), cohesive energy (φ), molecular force constant (f), Reststrahlen frequency (vo) and Grüneisen parameter (γ) are also analysed. © 2010 IOP Publishing Ltd.


Srivastava A.,Sri Sathya Sai College for Women | Gaur N.K.,Barkatullah University
AIP Conference Proceedings | Year: 2012

Silver-doped manganites are known for their huge magnetocaloric effect; hence their thermodynamic behaviour is mapped here with reference to the changed local environment at A-site due to silver doping. We present here, the theoretical formulation to calculate the temperature-dependent (2K < T < 350K) thermal expansion and specific heat of La1-xAg xMnO3 (x=0.05-0.50) using modified Rigid Ion Model (RIM) and AIM theory. The obtained results suggest that higher silver doping (x∼0.5) is favourable for the magnetocaloric application of manganites. © 2012 American Institute of Physics.


Gaur N.K.,Barkatullah University | Thakur R.,Barkatullah University | Thakur R.K.,Barkatullah University | Srivastava A.,Sri Sathya Sai College for Women
AIP Conference Proceedings | Year: 2013

Effect of heavy cation doping on thermal properties of perovskite PrCoO3 has been investigated by the means of a Modified Rigid Ion Model (MRIM). The specific heat and thermal expansion computed by us at temperature (1K ≤ T ≤ 300 K) of Pr0.5A0.5CoO 3 (A= Ca and Sr) are in reasonably good agreement with the available experimental data. Present investigations reaffirm the presence of strong electron-phonon interactions in these compounds. The results on cohesive energy and Debye temperature in orthorhombic and monoclinic perovskite phase are also discussed. © 2013 American Institute of Physics.


Srivastava A.,Sri Sathya Sai College for Women | Thakur R.,Barkatullah University | Gaur N.K.,Barkatullah University
AIP Conference Proceedings | Year: 2013

Specific heat (Cp), thermal expansion (α) and bulk modulus of sodium doped Rare Earth manganites R1-xNaxMnO 3(R3+=La,Pr,Tb) has been studied by means of a Modified Rigid Ion Model (MRIM) and AIM theory. The partial replacement of rare earth cation by sodium introduces large size and charge mismatch at A-site affecting the bulk modulus and thermal properties. Lattice specific heat (Cp) of Pr0.8Na0.2MnO3 as a function of temperature (1K≤T≤350K) is found to be in agreement with the published data. The trend of variation of Debye temperature with A-site cationic radius is predicted probably for the first time for the doped rare earth manganites. © 2013 AIP Publishing LLC.


Srivastava A.,Sri Sathya Sai College for Women | Thakur R.,Barkatullah University | Gaur N.K.,Barkatullah University
AIP Conference Proceedings | Year: 2013

The Specific heat of orthorhombic rare earth manganites RMnO3 (R = La-Dy) with 50% Calcium in the perovskite structure at A-site has been studied by means of a Modified Rigid Ion Model (MRIM). This replacement introduces large cation variance at A-site and change spin-ordering at B-site hence the specific heat increases appreciably. The lattice specific heat (C v) of Sm0.5Ca0.5MnO3 as a function of temperature (1K≤T≤ 300K) is found to be in agreement with the published data. The trend of variation of Debye temperature with A-site cation variance is predicted probably for the first time for the doped rare earth manganites. © 2013 AIP Publishing LLC.

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