The Effect of A-site Cation Variance on the Thermal and Elastic Properties of Half Doped Perovskite Manganites

Abstract

We investigate here the thermodynamic properties of orthorhombic half doped perovskite rare earth manganites R0.5Ca0.5MnO3 (R = La, Pr, Nd…Dy) by incorporating the effect of A‐site cation variance. The strong electron‐phonon interactions of these compounds are affected by lattice distortions due to A‐site size variance, charge mismatch (between Ca and R), MnO6, Jahn‐Teller octahedron distortions and buckling of Mn‐O‐Mn angle. The lattice contributions to the specific heat at constant volume (Cv(lattice)) of R0.5Ca0.5MnO3 has been studied as a function of temperature (10K⩽T⩽300K) by means of a Modified Rigid Ion Model (MRIM) and are found to be in agreement with the published data. Some other elastic, cohesive and thermal properties like bulk modulus (B), cohesive energy (φ), Debye Temperature (θD), molecular force constant (f), Reststrahlen frequency (νo) and Gruneisen parameter (γ) are also presented.