The thermal expansion and spontaneous magnetostriction of polycrystalline samples of Er1
xGdxMn6Sn6(0  x  1) intermetallics with hexagonal HfFe6Ge6-type structure are investigated in the emperature range of 77e520 K. The Gd substitution has significant effect on the interatomic distances and specially on inter-sublattice ReMn couplings. The replacement of Er by Gd causes the lattice constants to ncrease due to the larger atomic radius of Gd compared with Er. It also results in increasing the ordering temperature as well as the spontaneous magnetostriction values following reinforcement the ReMn coupling. The examined samples exhibit considerable thermal expansion anomalies at the Néel temperature (TN ¼ 340 and 335 K for the samples with x ¼ 0 and 0.2, respectively) and also at TM ¼ 309e 311 K where the Mn moments experience collapse-like reduction. Whereas, trivial anomalies are revealed at the Curie points (TC ¼ 77 K for the sample with x ¼ 0, 164 and 383 K for x ¼ 0.2, 419 and 434 K for x ¼ 0.6 and 1, respectively). From the results, it is concluded that the netovolume effects in these compounds originate mainly from the antiferromagnetic interlayer MneMn exchange interactions, and the intraplane ferromagnetism does not influence the magnetoelasticity.

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