Effect of cation doping on low-temperature specific heat of LaCoO3 cobaltate

We have computed the effect of strontium doping on the thermophysical properties of perovskite structure rare earth cobaltate, La1−xSrxCoO3 (0.0≤x≤1.0) by means of a rigid ion model (RIM) in the temperature 0 K2≤T2≤100 K2. The trends of variation of our computed specific heat with temperature are in agreement with corresponding experimental data. A meticulous attention was given to the investigation of the assumption that these cobaltate perovskites are Debye-like solids and obeys T3 law at low temperature (T<θD/50). Present investigations reaffirm the presence of strong electron–phonon interactions in these compounds. An interesting phenomenon was observed in Cp/T vs. T2 plot for x≤0.2 below 15 K where linearity deviates, which suggests the gradual freezing of the entropy on cooling. In addition, the results on bulk modulus (B), cohesive energy (ϕ), molecular force constant (f), restsrahlen frequency (υ), and Debye temperature(θD) are also presented. The scope of further extension of the present model has also been discussed.

► The negative values of cohesive energy show the stability of La1−xSrxCoO3 compounds.
► Our results on specific heat are in good agreement with the experimental data.
► The stability of La1−xSrxCoO3 (0.0≤x≤1.0) perovskite increases with the Sr substitution.