Lattice Dynamical Calculations for Inverse Spinel Compounds

Abstract

Lattice dynamical calculations have been performed for inverse spinel structure compounds MIn2S4 (M = Mn and Co) using the proposed six parameter bond-bending force constant model. In this model, the short-range force constant is calculated by using the Taylor expansion of the potential energy in the harmonic approximation. This model is applied to study the zone-centre (Γ = 0) phonon frequencies of inverse spinels MIn2S4 (M = Mn and Co). The signicant outcome of the present work is that the second neighbor interactions (octahedral bonding) are stronger than the rst neighbor interactions (tetrahedral bonding). The zone-center phonon frequencies, calculated using these parameters, are found to be in very good agreement with the observed results.