Effect of Co substitution on magnetic properties and magnetic entropy changes in LaFe_11.83Si_0.94Al_0.23 compounds

Effect of Co substitution on magnetic properties and magnetic entropy changes in LaFe_11.83Si_0.94Al_0.23 compounds has been investigated by means of magnetization measurements. X-ray diffraction shows the prepared compounds to be single phase with the cubic NaZn_13-type structure. Substitution of Co for Fe leads to an increase of Curie temperature of the material. The magnetic entropy changes in LaFe_11.83Si_0.94Al_0.23 and LaFe_11.03Co_0.80Si_0.94Al_0.23 compounds are 21.8J/(kg\cdotK) to 16.9J/(kg\cdotK) under a magnetic field change of 0－5T at Curie temperature, respectively. Giant magnetic entropy changes are attributed to the higher magnetization and the rapid change in magnetization at Curie temperature.