This article reports the first-principles study of SnO under high pressure within the generalized gradient approximation (GGA). We have calculated the structural, elastic, electronic and optical properties of SnO. The elastic properties such as the elastic constants Cij, bulk modulus, shear modulus, Young modulus, anisotropic factor, Pugh ratio, Poisson's ratio are calculated and analyzed. Mechanical stability of SnO at all pressure is confirmed using Born stability conditions in terms of Cij. It is also found that SnO exhibits very high anisotropy. The energy band structure and density of states are also calculated and analyzed. The results show the semiconducting and metallic properties at 0 (zero) and high pressure, respectively. Furthermore, the optical properties are also calculated. All the results are compared with those of the SnO where available but most of the results at high pressure are not compared due to unavailability of the results.

Mercury fluoro-perovskites based on Rubidium have a lot of technical relevance nowadays, especially in optical and semiconductive applications. A Cambridge Serial Total Energy Package code analysis using the Density Functional Theory was performed to calculate the structural, electronic, elastic, optical, and thermodynamic characteristics as well as the bonding nature of cubic fluoro-perovskites RbHgF3 under various hydrostatic pressures. To determine the total energy, the Perdew–Berke–Ernzerhof generalized gradient approximation was used to manage the exchange–correlation potential. The effects of hydrostatic pressure are studied in the region of 0–20 GPa, which maintains the cubic stable condition of RbHgF3 fluoro-perovskite. Experimental and prior theoretical results agree well with the calculated lattice parameters. When the pressure reached 20 GPa from 0 GPa, the volume, bond length, and lattice constant decreased. The bandgaps demonstrate an indirect band structure, with substantial reductions at various external forces. The total density of states reveals a non-metallic behavior. Mechanical properties satisfy the stability criteria until 20 GPa for this compound, and ductile behavior is also found within that pressure range. External stress modifies the optical characteristics a bit such as the complicated dielectric function, absorption, conductivity, and reflectivity. The presence of blue shift is confirmed by the movement of absorption edges toward higher energies, making this material an intriguing option for optical devices.

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Sr substituted perovskites La1.8Sr0.2MMnO6 (M = Ni, Co) were synthesized using solid state reaction technique to present a systematic study on their morphological, structural and magnetic properties. The average grain size of the as-prepared La1.8Sr0.2NiMnO6 samples are in the range of 0.2~0.7 µm and those for La1.8Sr0.2CoMnO6 manganites are 0.1~2.8 μm, which is significantly less than that of unsubstituted La2NiMnO6 (LNMO) and La2CoMnO6 (LCMO) manganites. The XPS analysis enlightened about phase purity, binding energy and oxygen vacancy of La1.8Sr0.2MMnO6 manganites. The Sr substituted LNMO has revealed a sharp ferromagnetic to paramagnetic phase transition at 160±2 K which is about 120 K less than that of parent LNMO. The Sr substituted LCMO exhibited such a transition at 220±2 K which is 8 K less than that of parent LCMO. The temperature dependent magnetization measurements suggest that the effect of Sr on the transition temperature in LNMO is more significant than that of LCMO.