Thermal expansion of RIn3 compounds with R=Pr, Gd and Lu

Results of the linear thermal expansion coefficient α(T) measurements for PrIn3, GdIn3 and LuIn3 are reported. These rare earth intermetallic compounds belong to a large family of RIn3 compounds which crystallize in AuCu3-type crystal structure. The measurements were made on monocrystalline samples in temperature range 5 K/200 K. The compounds under investigation differ in their magnetic properties: PrIn3 is a typical example of a singlet ground-state paramagnet in which the interionic interactions are quenched by the crystalline electric field (CEF), whereas GdIn3 is the crystal-field free antiferromagnet in which the interionic RKKY interactions play essential role and cause the antiferromagnetic structure which is still unknown. The results of the measurements for LuIn3 served as a non-magnetic background for the separation of the contribution to α(T) arising from the magnetic interaction. Theoretical considerations concerning the influence of CEF on the thermal expansion are remined. Pertinent Grueneisen parameters will be estimated in a forthcoming paper. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)