Enhanced magnetocaloric properties in off-stoichiometric La x Fe 11.5 Si 1.5 alloys

Abstract In this paper, we report on the microstructure and magnetocaloric effect in off-stoichiometric La x Fe 11.5 Si 1.5 alloys. The X-ray diffraction and microstructural analysis indicate that the atomic ratio of Fe:Si in the main 1:13 phase is modified by adding excessive La. The off-stoichiometric alloys exhibit lower Curie temperatures and larger thermal hysteresis when comparing with the x  = 1.0 alloy. The maximum isothermal entropy change is enhanced by 15% when the excessive La content is x  = 1.2. The present study offers an effective and simply way to improve the magnetocaloric effect in such La-Fe-Si alloys.