Influence of A-Site cation size-disorder on the magnetocaloric response of La0.6CaxSr0.4-xMnO3 nanoparticles

Building on previous work finding a significant magnetocaloric effect (MCE) in manganite nanoparticles having the formula La0.60Cax Sr0.40-xMnO3 (0<x<0.4), which show promise for application in magnetic refrigeration systems. These were synthesized via a Pechini sol-gel method, as verified by powder x-ray diffraction and laser ablation-inductively coupled plasma-mass spectrometry. The temperature-dependence of the magnetic entropy change between 200K and 320K in a magnetic field of μH=3T was evaluated by means of Maxwell’s relations and isothermal MH curves. The reported values of ΔSmax increase from 1.5 J kg-1K-1 to 5.6 J kg-1K-1 as x increases from 0 to 0.4. Ms; crystallite size and b and c lattice parameters increase with x. The results show a clear positive correlation between calcium concentrations and the value of -ΔS, suggesting that a larger atom at the calcium site negatively impacts the magnetocaloric effect, thereby decreasing magnetic refrigeration viability.