Structural and magnetic properties of RET2Sn2 compounds (RE=La, Ce, Sm; T=Ni, Cu)

The following compounds have been synthesized: LaCu2Sn2, CeCu2Sn2, SmCu2Sn2 and SmNi2Sn2. By means of X-ray diffraction their structure was determined to be primitive tetragonal of CaBe2Ge2-type (space group P4/nmm) and the lattice parameters were obtained.119Sn Mossbauer measurements were performed in a temperature range between 4.2 K and 300 K. The temperature dependence of the Lamb-Mossbauer factor reveals considerable softening of lattice vibration modes below 160 K. Only SmCu2Sn2 orders magnetically above 4.2 K.