Temperature and field dependence of the spin magnetization density in SmMn2Ge2 -: art. no. 024407

The site specific spin moments in the layered intermetallic compound SmMn2Ge2 have been measured directly as a function of field, between 0.02 and 1 T, using the spin-polarized Compton scattering technique at 13, 40, and 230 K. The field dependence of the orbital moment has been determined by comparison at each temperature with magnetometry data. A small finite Sm spin moment is observed at a low applied field of 0.02 T. These data indicate that in the high-temperature ordered phase the rare-earth sites exhibit a small net moment and exhibit paramagnetic behavior with little coupling to the Mn spin sublattice. Our low-temperature, low-field data indicate a change in magnetic order of the Sm site at approximate to35 K that is metamagnetic in nature. However, we find no evidence for a zero-field transition in the Sm sublattice as previously suggested.