The effects of Tb substitution for La on the magnetic properties of LaFe11.5Si1.5 compound

The structural and magnetic properties of La1−yTbyFe11.5Si1.5 compounds have been investigated. The substituted 5 percent of Tb has remarkably increased the maximum entropy change (−ΔSM) to a value of 25.2 J/kg·K. However, a further increase of Tb leads to a monotonous decrease in the entropy change, mainly due to phase separation. The Tb substitution also can lower the thermal and magnetic hysteresis loss of the system. Another feature of this replacement is that, with Tb content higher than 10 percent, the Curie temperature (TC) starts to increase and reaches 197 K when 30 percent of La is substituted. These results indicate that La1−yTbyFe11.5Si1.5 may be a promising candidate for magnetic refrigeration material in certain temperature range.