Large magnetocaloric effects in Pr-doped La1.4-xPrxCa1.6Mn2O7 bilayer manganites

Abstract

Controlled substitution of Praseodymium (Pr) in place of Lanthanum (La) was performed in La1.4-xPrxCa1.6Mn2O7 (x = 0.0, 0.1, 0.2, 0.3 and 0.4) to explore a possible enhancement in the magnetic and magnetocaloric properties of the material. The samples were produced following the solid-state reaction route. Rietveld refined XRD profiling was used that established the bilayer tetragonal structure (I4/mmm) of the Ruddlesden-Popper Phase in all compositions. Significant variations in the unit cell parameter were observed upon incorporation of Pr in place of La. Ferromagnetic to paramagnetic transitions were confirmed from the temperature dependent magnetization. Against the pristine sample, multiple folds increase was achieved in the values of magnetic entropy change (ΔSM) as well as the temperature averaged entropy change (TEC) with controlled Pr-substitution in the doped samples. Highest ΔSM and TEC (ΔTH-C = 10 K) values of 6.16 J kg −1K−1 and 8.329 J kg −1K−1 respectively were obtained in the x ≥ 0.3 samples at 2.5 T applied field. Our findings in this work suggest giant magnetocaloric effects in the Pr-doped samples and support the possibility of further tailoring these materials for applications in magnetic refrigeration technology.