Lattice Dynamical Study and Elastic Property of Europium Telluride (Eute) Crystal

In the present work authors are reporting complete lattice dynamical properties of Europium telluride (EuTe). The present model works on three body rigid ion model & three body rigid shell model (TRIM & TRSM). The short-range overlap repulsion is operative up to the second neighboring ions. An excellent agreement has been obtained between theory and experiment for their all-phonon properties of (EuTe) like phonon dispersion curves, Debye temperature variations, two-phonon IR/Raman spectra, third-fourth order lattice constant, pressure derivative and anharmonic elastic properties.

Lattice dynamical and elastic properties of BaFX (X = Cl, Br and I): Matlockite structure compounds

In this study, an eleven-parameter rigid-ion model (RIM) is proposed for BaFX (X = Cl, Br and I) matlockite structure compounds. The interatomic interactions up to fourth nearest neighbors for the studied compounds are calculated. The zone-center raman and infrared phonon mode frequencies, elastic constants, bulk modulus B, shear modulus G, Young’s modulus E, Poisson’s coefficient, Debye temperature and sound velocity along [100], [110] and [001] directions have been calculated. It is observed that the studied BaFCl, BaFBr and BaFI compounds are stiffer in [100] direction than [001] crystallographic direction and the bulk modulus, shear modulus and Young’s modulus of the studied compounds decrease in the order of BaFCl [Formula: see text] BaFBr [Formula: see text] BaFI. The obtained results are compared with the theoretical and experimental results. It is observed that the obtained results agree very well with the experimental and theoretical results available in the literature.

Vibrational, mechanical and thermodynamical properties of indium thiospinelsMIn2S4(M= Cd, Zn and Mg)

In this paper, interatomic interactions, zone-center phonon frequencies, mechanical properties, sound velocities and Debye temperature of indium thiospinels MIn2S4(M = Cd, Zn and Mg) have been calculated using rigid-ion model. We found that the first neighbor interaction is stronger than the second neighbor interaction. We have compared our calculated results with the available experimental and theoretical data and find good agreement with the experimental results.

A unified description of the double perovskite family Sr2MWO6 within a rigid ion model

The sequence of phase transitions and structural instabilities of the Sr2MWO6 double perovskites are investigated using a rigid ion model.

Thermodynamic Properties of La1-xSmxCoO3

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).

Elastic and Thermal Properties of SrCo1-xScxO3-δ

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.

Effect of Cd Doping on Mechanical Properties of SrCoO3

We have investigated the elastic and thermal properties of Sr1-xCdxCoO3 (0=x=0.1) probably for the first time by means of modified rigid ion model (MRIM). In this paper, we present the second order elastic constants (SOECs) and other elastic properties like Bulk modulus (B), Young's modulus (Y), Shear modulus (G), ̠̹̿̓̓̿̾˷̓˰̱̹͂̈́̿˰˸σ˹˼˰̵̜̱̽˷̓˰̵̵̱̱̀͂̽̈́͂˰˸m, l), transverse, longitudinal, ˰̵̷̵̱̱͆͂˰̵͇̱͆˰̵̼̳̹͉͆̿̈́˰˰˸υt, υl˼˰υm) and Anisotropy parameter (A). Here, the SOECs for Sr1-xCdxCoO3 compounds are positive and satisfy the generalized criteria for mechanically stable crystals: (C11-C12) > 0, (C11+2C12) > 0 and C44 > 0 which confirm that Sr1-xCdxCoO3 (0=x=0.1) belong to metallically bonding materials.

ELASTIC AND THERMAL PROPERTIES OF Sr1-xCaxRuO3

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).

Electrocaloric and electrostrictive effect of polar P(VDF–TrFE–CFE) terpolymers

The electrocaloric effect (ECE) is the adiabatic temperature change or isothermal entropy change caused by the polarization change of a dielectric material when subjected to a change of external electric field. The electrostrictive effect is a form of elastic deformation of a dielectric induced by an electric field, associated with those components of strain which are independent of reversal field direction. It was found that both the ECE, e.g., adiabatic temperature change, and the electrostrictive strain in poly(vinylidene fluoride–trifluoroethylene–chlorofluoroethylene) (P(VDF–TrFE–CFE)) terpolymers are proportional to the square of the electric field. The adiabatic temperature change ΔT of ECE versus electric field can be illustrated using a modified Belov–Goryaga equation. ΔT is proportional to E2 when E is small. For electrostrictive effect, the rigid-ion model assumes that the anharmonic movement of the ions leads to the quadratic strain–electric field relation. The quotient of electrostrictive coefficient Q over the phenomenological coefficient β is empirically a constant, indicating that the larger the electrostrictive coefficient, the larger the ECE, which opens a new way to find out new electrocaloric materials.

SPECIFIC HEAT OF Tb0.5Sr0.5CoO3 CERAMICS

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.