PHONON DEPENDENCE ON THERMAL PROPERTIES OF RGaO3(R = La, Ce, Nd, Pr, Sm, Gd)

2012 ◽  
Vol 01 (01) ◽  
pp. 1250006
Author(s):  
ATAHAR PARVEEN ◽  
N. K. GAUR
Keyword(s):  
Experimental Data ◽  
Thermal Properties ◽  
Rare Earth ◽  
Bulk Modulus ◽  
Specific Heat ◽  
Temperature Dependence ◽  
Debye Temperature ◽  
Van Der Waals Interactions ◽  
Cohesive Properties ◽  
Rigid Ion Model

We have systematically investigated the effect of phonons on elastic, thermal and cohesive properties for rare earth gallates RGaO3 (R = La, Ce, Nd, Pr, Sm, Gd) by means of a Rigid Ion Model after modifying its framework to incorporate the van der Waals interactions. Besides that, we have calculated the temperature dependence of the specific heat for the present orthogallates. The results on bulk modulus, Debye temperature and specific heat reproduce well with the available experimental data.

scholarly journals Thermodynamic Properties of La1-xSmxCoO3

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Rasna Thakur ◽  
N. K. Gaur
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Bulk Modulus ◽  
Specific Heat ◽  
Specific Heats ◽  
Lattice Specific Heat ◽  
Lattice Distortions ◽  
First Time ◽  
Rigid Ion Model

We have investigated the bulk modulus and thermal properties of La1-xSmxCoO3 (0≤x≤0.2) at temperatures 1 K≤T≤300 K probably for the first time by incorporating the effect of lattice distortions using the modified rigid ion model (MRIM). The calculated specific heat, thermal expansion, bulk modulus, and other thermal properties reproduce well with the available experimental data, implying that MRIM represents properly the nature of the pure and doped cobaltate. The specific heats are found to increase with temperature and decrease with concentration (x) for the present. The increase in Debye temperature (θD) indicates an anomalous softening of the lattice specific heat because increase in T3-term in the specific heat occurs with the decrease of concentration (x).

SPECIFIC HEAT OF Tb0.5Sr0.5CoO3 CERAMICS

2013 ◽  
Vol 22 ◽  
pp. 391-396
Author(s):  
RASNA THAKUR ◽  
RAJESH K. THAKUR ◽  
N. K. GAUR
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
Specific Heat ◽  
Debye Temperature ◽  
Cohesive Energy ◽  
Grüneisen Parameter ◽  
Temperature Range ◽  
Proper Interpretation ◽  
Rigid Ion Model

We have investigated the thermal and allied properties of Tb0.5Sr0.5CoO3 for the temperature range 1K≤T≤300K using the Modified Rigid Ion Model (MRIM). The calculated bulk modulus, specific heat, and other thermodynamic properties obtained from MRIM have presented proper interpretation of the experimental data, for Sr ions doped TbCoO3 . In addition, the results on the cohesive energy (φ), Debye temperature (θD) and Gruneisen parameter (γ) are also discussed.

LOW TEMPERATURE SPECIFIC HEAT OF INTERMETALLICS (Ti/Be)B2

2007 ◽  
Vol 21 (14) ◽  
pp. 885-891 ◽  
Author(s):  
NUPINDER KAUR ◽  
N. K. GAUR ◽  
R. K. SINGH
Keyword(s):  
Experimental Data ◽  
Thermal Properties ◽  
Low Temperature ◽  
Specific Heat ◽  
Debye Temperature ◽  
Cohesive Energy ◽  
Specific Heats ◽  
Molecular Force ◽  
Low Temperature Specific Heat ◽  
Rigid Ion Model

We have applied the Rigid Ion Model (RIM) to study the cohesive and thermal properties of binary intermetallic BeB 2 and TiB 2. The paper reports the calculated results on cohesive energy (ϕ), compressibility (β), molecular force constant (f), Restrahalen frequency (ν0), Debye temperature (Θ D ) and Gruneisen parameter (γ) for the temperature range 50 K ≤ T ≤ 300 K and the effect of van der Waal interaction on these properties are also shown. Our results on Debye temperature are closer to the experimental data. In addition, we have computed the specific heats for BeB 2 and TiB 2 and compared them with the available experimental data.

ELASTIC AND THERMAL PROPERTIES OF Sr1-xCaxRuO3

2013 ◽  
Vol 27 (17) ◽  
pp. 1350054 ◽  
Author(s):  
RASNA THAKUR ◽  
RAJESH K. THAKUR ◽  
N. K. GAUR
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Specific Heat ◽  
Debye Temperature ◽  
Cohesive Energy ◽  
Molecular Force ◽  
Almost All ◽  
Good Agreement ◽  
Rigid Ion Model

We have investigated the elastic and thermal properties of Sr 1-x Ca x RuO 3(0≤x ≤1) perovskite using a modified rigid ion model (MRIM). The trend of variation of our computed specific heat in the temperature range 1 K ≤ T ≤ 1000 K are in good agreement with corresponding experimental data for almost all the compositions (x). The specific heat found to increase with temperature from 1 K to 300 K, while they decrease with concentration (x) for these perovskite ruthenates. Besides, we have reported the thermal properties, like thermal expansion (α), molecular force constant (f), Reststrahlen frequency (υ), cohesive energy (ϕ), Debye temperature (θD) and Gruneisen parameter (γ).

THE ELASTIC AND THERMODYNAMIC PROPERTIES OF Lu DOPED ScVO3

2012 ◽  
Vol 26 (31) ◽  
pp. 1250190
Author(s):  
ATAHAR PARVEEN ◽  
N. K. GAUR
Keyword(s):  
Experimental Data ◽  
Thermal Properties ◽  
Phase Transitions ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Structural Phase ◽  
Magnetic Ordering ◽  
Structural Phase Transitions ◽  
Lattice Distortions ◽  
Rigid Ion Model

We have investigated the elastic, cohesive and thermal properties of (Lu, Sc) VO 3 and Sc 1-x Lu x VO 3(0.6 ≤ x ≤ 0.9) perovskites by means of a modified rigid ion model (MRIM). The variation of specific heat is determined following the temperature driven structural phase transitions. Also, the effect of lattice distortions on the elastic and thermal properties of the present pure and doped vanadates has been studied by an atomistic approach. The calculated bulk modulus (BT), reststrahlen frequency (ν0), cohesive energy (ϕ), Debye temperature (θD) and Gruneisen parameter (γ) reproduce well with the corresponding experimental data. The specific heat results can further be improved by including the magnetic ordering contributions to the specific heat.

Pressure Induced Properties of UXLa1-XS Compound

2016 ◽  
Vol 28 ◽  
pp. 108-114
Author(s):  
Ashok K. Ahirwar ◽  
Mahendra Aynyas ◽  
Sankar P. Sanyal
Keyword(s):  
Experimental Data ◽  
Phase Transition ◽  
Thermal Properties ◽  
Bulk Modulus ◽  
Debye Temperature ◽  
Elastic Constants ◽  
Volume Change ◽  
Mechanical And Thermal Properties ◽  
Phase Transition Pressure ◽  
Crystal Structural

The crystal structural, mechanical and thermal properties of UXLa1-XS compound with different concentrations (x= 0.00, 0.08 and 0.40) are investigated using modified inter-ionic potential theory (MIPT), which parametrically includes the effect of coulomb screening by the delocalized f-electrons. Our calculated values of phase transition pressure, bulk modulus and volume change are agree well with the theoretical and experimental data. We have also calculated the second order elastic constants and Debye temperature of these three concentrations.

Elastic and Thermal Properties of SrCo1-xScxO3-δ

2014 ◽  
Vol 975 ◽  
pp. 283-287
Author(s):  
Rasna Thakur ◽  
Rajesh K. Thakur ◽  
N.K. Gaur
Keyword(s):  
Thermal Properties ◽  
Specific Heat ◽  
Debye Temperature ◽  
Elastic Constants ◽  
Cohesive Energy ◽  
Second Order ◽  
Grüneisen Parameter ◽  
Gruneisen Parameter ◽  
Rigid Ion Model

We have investigated the elastic and thermal properties for perovskite SrCo1-xScxO3-d, by means of Modified Rigid Ion Model (MRIM). We have also computed the second order Elastic constants (SOECs) and their combinations. Besides we have reported the cohesive energy (f), Debye temperature (θD) and Gruneisen parameter (γ). The variation of specific heat (C) at temperature 15 K≤x≤1000 K is computed for SrCo1-xScxO3-d. The computed properties reproduce well with the available data in literature.

Vibrational Spectrum and Specific Heat of Tantalum

1971 ◽  
Vol 49 (21) ◽  
pp. 2727-2730 ◽  
Author(s):  
Satya Pal
Keyword(s):  
Experimental Data ◽  
Vibrational Spectrum ◽  
Specific Heat ◽  
Debye Temperature ◽  
Fair Agreement ◽  
Dynamical Model

The vibrational spectrum and specific heat of tantalum are calculated on the basis of the lattice dynamical model of Sharma and Joshi. The calculated specific heat and the corresponding equivalent Debye temperature show fair agreement with the experimental data of Clusius and Losa.

scholarly journals Temperature dependence of optical linewidths and specific heat of rare-earth-doped silicate glasses

1993 ◽  
Vol 71 (18) ◽  
pp. 3031-3034 ◽  
Author(s):  
Th. Schmidt ◽  
J. Baak ◽  
D. A. van de Straat ◽  
H. B. Brom ◽  
S. Völker
Keyword(s):  
Rare Earth ◽  
Specific Heat ◽  
Temperature Dependence ◽  
Silicate Glasses ◽  
Rare Earth Doped

scholarly journals Theoretical Investigations of Structural Phase Transitions and Magnetic, Electronic and Thermal Properties of DyNi: Under High Pressures and Temperatures

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Pooja Rana ◽  
U. P. Verma
Keyword(s):  
Thermal Properties ◽  
Rare Earth ◽  
Bulk Modulus ◽  
Density Functional ◽  
High Pressures ◽  
Magnetic Moments ◽  
Structural Phase ◽  
Rare Earth Ions ◽  
Full Potential ◽  
Electronic Band

Present work is influenced by the requirement of investigation of rare earth intermetallics due to the nonavailability of theoretical details and least information from experimental results. An attempt has been made to analyse the structural, electronic, magnetic and thermal properties of DyNi using full potential linear augmented plane wave method based on density functional theory. DyNi differs from other members of lanthanides nickelates as in ground state it crystallizes in FeB phase rather than orthorhombic CrB structure. The equilibrium lattice constant, bulk modulus, and pressure derivative of bulk modulus are presented in four polymorphs (FeB, CrB, CsCl and NaCl) of DyNi. At equilibrium the cell volume of DyNi for FeB structure has been calculated as 1098.16 Bohr3 which is comparable well with the experimental value 1074.75 Bohr3. The electronic band structure has been presented for FeB phase. The results for thermal properties, namely, thermal expansion coefficient, Gruneisen parameter, specific heat and Debye temperature at higher pressure and temperatures have been reported. The magnetic moments at equilibrium lattice constants have also been tabulated as the rare earth ions associated with large magnetic moments increase their utility in industrial field for the fabrication of electronic devices due to their magnetocaloric effect used in magnetic refrigeration.

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