Magnetocaloric effect in the Ce2Fe17−xMnx helical magnets

► The MCE exhibits peaks at ΘT, TN for x = 0-0.35, 1.3-2 and at TN for x = 0.5-1. ► The MCE is inverse in a narrow temperature interval just below TN. ► The maximal change of the peak entropy is 3 J/kg K at 230 K for Ce2Fe17. ► The peak entropy change decreases by half in the Ce2Fe17−xMnx (x = 0-2) system. ► The helical magnetic structures in Ce2Fe17−xMnx badly contribute to the low MCE.