Thermal expansion of filled skutterudite compound GdRu4P12

Abstract

We have performed X-ray diffraction and thermal expansion measurements at low temperatures of the filled skutterudite compound GdRu4P12 in order to investigate structural changes related to the antiferromagnetic phase transition at TN=22K. No significant change in the X-ray powder diffraction pattern of GdRu4P12 was detected down to 10K. The variation of thermal expansion is continuous at TN. Therefore, the transition is not accompanied with any crystallographic transformation. The temperature dependence of the linear thermal expansion coefficient shows large jump (1.2 × 10-6 K-1) at TN. This value is comparable to that of isostructual compound SmRu4P12 at the metal-insulator transition temperature TMI=16K.