Structural and elastic properties of Ca-substituted LaMnO3 at 300 K

The compositional dependence of structural and elastic properties of Ca2+ substituted manganite perovskite system with a general formula La1-xCaxMnO3 (x = 0.00, 0.25, 0.33, 0.50 and 1.00) have been studied by means of x-ray diffraction, scanning electron microscopy and ultrasonic pulse transmission technique at 300 K. The elastic moduli of the specimens have also been computed and these are corrected to the void free state. The lattice parameters calculated theoretically are in agreement with those determined experimentally. The structural-elastic properties correlations have been studied. The observed enhancement of elastic constants up to x = 0.33 and reduction with a further increase in calcium concentration has been explained in the light of change in the strength of interatomic bonding caused by change in interatomic distances, microstructure and electronic configuration. The applicability of the heterogeneous metal mixture rule for theoretical estimation of elastic constants has been tested.