Magnetic Phase Transitions in R5Pd2 (R = Ho, Dy, Dy0.6Gd0.4) Compounds

R 5 Pd 2 compounds are known to exhibit magnetic glass transition and large cooling power in the cryogenic temperature region. All the R 5 Pd 2 (R = Ho, Dy, Dy 0.6 Gd 0.4 ) compounds crystallize in the cubic Dy 5 Pd 2 -type of structure (space group Fd 3 m). The compounds Ho 5 Pd 2 , Dy 5 Pd 2 , and (Dy 0.6 Gd 0.4 ) 5 Pd 2 undergo a paramagnetic to glass transition at 27 K, 38 K, and 58.5 K with a small hump at 10 K, 14 K, and 20 K respectively, confirming the double glass transitions present in these compounds. The maximum isothermal magnetic entropy changes (− Δ S max ) for the compounds Ho 5 Pd 2 , Dy 5 Pd 2 , and (Dy 0.6 Gd 0.4 ) 5 Pd 2 are 19.95 J/kg-K, 7.89 J/kg-K, and 7.4 J/kg-K with RCP values 987 J/kg, 549 J/kg, and 673 J/kg respectively for magnetic field change of 70 kOe. However, there is a controversy regarding the order of magnetic phase transition present in these compounds. A detailed investigation on the order of magnetic phase transition in Ho 5 Pd 2 , Dy 5 Pd 2 , and (Dy 0.6 Gd 0.4 ) 5 Pd 2 compounds has been studied. Heat capacity measurements give a fingerprint of the absence of first-order magnetic phase transitions in these compounds. Field dependent magnetic entropy change studies on these compounds confirm the second-order nature of magnetic phase transitions.