Abstract: The structural and magnetic properties of Pr_0.1Ce_xTb_0.9-xFe_1.9 alloys were investigated by using X-ray diffraction, AC susceptibility, VSM and standard strain gauge techniques. The lattice parameter exhibits positive deviation from Vegard's law with the increasing Ce content in the range of 0.4-0.6. Curie temperature decreases linearly with increasing Ce content. The saturation magnetization and magnetostriction decrease when 0.2≤x＜0.4 and x＞0.6, while abnormally increase with Ce content increasing from 0.4 to 0.6. These abnormal changes of lattice parameter, saturation magnetization and magnetostriction can be attributed to the valence fluctuation of Ce ions.

Key words: magnetostriction; laves phase; Pr_0.1Ce_xTb_0.9-xFe_1.9 alloy; valence fluctuation