Thermal expansion and magneto striction in Pr/sub 5/Ni/sub 2/Si/sub 3/ compounds

The thermal expansion and magnetostriction of polycrystalline and single-crystal Pr/sub 5/Ni/sub 2/Si/sub 3/ were investigated over the temperature range 5-300 K. The results show two magnetic phase transitions, one corresponding to the Curie temperature and the other at a lower temperature exhibiting characteristics of a spin reorientation transition. In the temperature range below the Curie temperature, the thermal expansion in single-crystal samples exhibited a temperature dependent anisotropy. Specifically negative and positive magnetic contributions to the thermal expansion were observed along the directions parallel and perpendicular to the c axis respectively.