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

A very large magnetic entropy change DeltaS has been observed in Fe-based cubic NaZn13-type compound LaFe11.2Co0.7Si1.1 near the Curie temperature T-C of 274 K. The value of the entropy change is similar to20.3 J/kg K under a magnetic field of 5 T at T-C=274 K. It markedly exceeds that of pure Gd at the corresponding temperature range [V. K. Pecharsky & K. A. Gschneidner, Jr., Phys. Rev. Lett. 78, 4494 (1999)]. The great entropy change produced by the sharp change of magnetization is associated with a large negative lattice expansion at T-C. The very large magnetic entropy change and low cost suggest that the compound LaFe11.2Co0.7Si1.1 has great potential for applications as magnetic refrigerants near room temperature. (C) 2002 American Institute of Physics.