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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. Source


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 Source


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. Source


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 Source


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. Source

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