and 7 T, respectively. Despite of the fact that the values of MCE parameters ( SMmax, admax and RCP) for EuCu1.75P2 are smaller than those of which processed the first order magnetic transitions, the present values are comparable with those of which undergoing the second order magnetic transitions. The giant reversible anisotropic MCE in antiferromagnetic EuFe2As2 single crystal was attributed to the first order magnetic transitions in a-b plane and the second order magnetic transitions out-of-plane.[23] The maximum value of the out-of-plane magnetic entropy change for field changes of 5 T is 10.3 J kg-1 K-1, which is comparable with the value of 10.7 J kg-1 K-1 for our ferromagnetic EuCu1.75P2 polycrystalline sample. The present EuCu1.75P2 compound exhibits a high reversible MCE, which makes it to be competitive materials for active magnetic-refrigeration application.

Conclusions

In summary, the critical behaviour and magnetocaloric effect in EuCu1.75P2 were systematically investigated by determining the magnetization and heat capacity. The estimated values of , and is determined to be 0.45±0.03, 1.22±0.04, and 3.71±0.07, respectively. The observed reversible MCE around 51 K is related to a second-order magnetic phase transition. The maximum values of magnetic entropy change (- SMmax) reach 5.6 and 10.7 J kg-1 K-1 for the field change of 2 and 5 T, respectively. The corresponding values of relative cooling power are 101 and 331 J/kg. The present results may give some clue for searching new materials with large MCE.

Acknowledgements

This work was partially supported by the National Natural Science Foundation of