Effect of Covalence and Degree of Cation Order on the Luminous Efficacy of Mn Luminescence in the Double Perovskites, BaTaO ( = Y, Lu, Sc).

The spectroscopic properties of the Mn ion are investigated in the series of isostructural double perovskite compounds, BaTaO ( = Y, Lu, Sc). A comparison of these properties highlights the influence of covalent bonding within the perovskite framework and the degree of order between the B-Ta cations on the energy and intensity of the MnE → A emission transition (R-line). These two parameters of the emission spectrum are of importance for practical application since they determine the phosphor luminous efficacy.

Influence of Isostatic Pressure on the Elastic and Electronic Properties of KSiF:Mn.

Isostatic pressure effects on the elastic and electronic properties of non-doped and Mn-doped KSiF (KSF) have been investigated by first-principles calculations within density functional theory (DFT). Bulk modulus was obtained by the Murnaghan's equation of states (EOS) using the relationship between volume and pressures at pressures between 0 and 40 GPa, and elastic constants were calculated by the stress-strain relationship giving small distortions at each pressure point. The other elastic parameters such as shear modulus, sound velocity and Debye temperature, which can be obtained from the elastic constants, were also estimated.