Thermal expansion anomaly of Pr2AlFe13Mn3 compound near its Curie temperature and magnetic properties of Pr2AlFe16−xMnx compounds

Abstract

Structure and magnetic properties of Pr2AlFe16−xMnx (x=0–10) compounds have been investigated by means of x-ray diffraction and magnetization measurements. The Pr2AlFe16−xMnx compounds have a rhombohedral Th2Zn17-type structure. Their unit-cell volume increase slowly with increasing x, then rapidly with the further increase of x. This implies a strong positive spontaneous volume magnetostriction exists in the magnetic state for Pr2AlFe16−xMnx compounds. X-ray diffraction of Pr2AlFe13Mn3 compound from 160 to 300 K shows that a negative coefficient of thermal expansion exists, ᾱ≈−3.6×10−4/K, from 180 to 198 K. The Curie temperature and the saturation magnetization of Pr2AlFe16−xMnx compounds show a rapid drop with increasing x.