Effect of Pr and Co substitution on magnetic properties and magnetic entropy changes in LaFe13−xSix compounds

Effect of Pr and Co substitution on magnetic properties and magnetic entropy changes in the cubic NaZn13-type compound LaFe11.2Si1.8 has been experimentally investigated. Replacing 30 at.% La with Pr leads to a decrease of Curie temperature from 216 to 203 K, and drives the magnetic transition from second-order to first-order. As a result, magnetic entropy change, under a field change of 0–5 T, increases from 13.7 to 19.4 J/kg K. Substitution of Co for Fe in La07Pr0.3Fe11.2Si1.8 can adjust TC to around room temperature. A magnetic entropy change of 9.3 J/kg K at TC = 290 K for a field change from 0 to 5 T is obtained in La07Pr0.3Fe10.4Co0.8Si1.8. A reversible variation of magnetization with temperature and magnetic field is observed in the present compound, which is highly desired by the magnetic refrigeration application.