Magnetocaloric effect in nano- and polycrystalline La0.8Sr0.2MnO3 manganites

The sol–gel method is applied to prepare the polycrystalline La0.8Sr0.2MnO3 manganite and to reduce grain sizes of nanocrystalline sample down to 23 nm. The magnetocaloric effect was determined from isothermal magnetization measurements. Transition from the polycrystalline to nanocrystalline structure reduces the size of magnetocaloric effect and markedly broadens the temperature interval over which it occurs. The relative cooling power RCP(S) = 35 J/kg in polycrystalline manganite remains almost the same in the nanocrystalline case.