Magnetic properties of the SmMn2(Ge1–<i>x</i>Si<i>x</i>)2 system

Abstract

Magnetization and thermal expansion measurements have been carried out on the polycrystalline SmMn2(Ge1–xSix)2 system (x=0.00, 0.01, 0.02, 0.03, 0.05, 0.08, 0.10, 0.12, and 0.15) to study its magnetic properties. It is found that the temperature range of stability of the antiferromagnetic region increases with the increase of Si content. This behavior is explained as a decrease in the Mn–Mn intralayer separation. Ferro- to antiferromagnetic (T2) and antiferro- to ferromagnetic (T1) transitions are found to be first order for all the samples up to x=0.10. For x=0.15 sample the antiferro- to ferromagnetic (T1) transition is of first order while the ferro- to antiferromagnetic (T2) transition appears to be second order. A magnetic phase diagram of SmMn2(Ge1–xSix)2 has been determined.