Magnetic properties of the Sm1-xCexMn2Ge2 system

Magnetic properties of polycrystalline Sm1-xCexMn2Ge2 (0≤x≤1) compounds have been studied by magnetic susceptibility measurements. A magnetic phase diagram has been constructed. The SmMn2Ge2 sample shows re-entrant ferromagnetism with a ferromagnetic (FM) transition at T1=341 K, a FM to antiferromagnetic (AF) transition at T2=144 K, an AF to FM transition at T3=105 K, and then a Sm-ordering-related FM transition at TSm∼20 K. As x increases, (i) T1 and T2 decrease, (ii) T3 increases initially and then decreases beyond x=0.011, and (iii) TSm remains unchanged up to x=0.1 and then decreases rapidly. The AF phase is destroyed at x=0.011. The AF region width ΔTAF (=T2-T3) varies with RaMn-Mn at a rate about ten times as fast as that in Sm1-xGdxMn2Ge2. Our results suggest that T3 can be affected by both the intralayer Mn-Mn distance and the spin disorder in the rare-earth layers. (orig.)