Very large magnetic entropy change near room temperature in LaFe11.2Co07Si11

Very large magnetic entropy change has been observed in the Fe-based cubic NaZn13-type compound LaFe11.2Co07Si11near the Curie temperature TC of 274K. The value of this change is ～20.3J/kg K under a magnetic field of 5T at TC=274K， which markedly exceeds that of pure Gd by a factor of 2 in the corresponding temperature range. The strong structural and magnetic interplay in the compounds, characterized by the drastic lattice contraction at TC, is presumably responsible for this great entropy change.